Blip switch redundant ?

[HagarTheHorrible]

I've asked this before, but, having read a bit more about flying with rotaries I think I understand better about why it was used, and it's not really the way it's used in FC.  Indeed from my prespective I think it's pretty redundant in the sim.

 

In real life, from what I understand, the fuel mixture of a rotary engine has to be adjusted everytime you move the throttle, which is probably a bit of a pain in the backside, more so because it probably needs to be done when the pilot most needs his head out of the cockpit and not staring at gauges and fiddling with his knob.  At the moment, in FC, the throttle is used with no regard to mixture, we simple open or close the throttle as needed. If we need to reduce RPM's in a dive we reduce throttle, if we want to slow down, we reduce throttle, the only time mixture comes into play is adjusting for full RPM at full throttle and the occasional nudge for altitude.  The BLIP switch, in reality was to allow the pilot to do these things without having to start faffing about with the mixture, the engine could be managed without regard to the throttle and it's wayward cousin, the mixture control.

 

I know some people say they use the BLIP switch, but it's not really doing the job it was designed for, indeed you could fly for an entire lifetime in FC, as it stands, and never even know the blip switch exists or what it's job is or feel in any way hindered by this lack of knowledge.

 

Should it do the job for which it was designed, or is it irrelevant to playing the sim  and not required ?

[Zooropa_Fly]

It's certainly not as responsive as it was in RoF, there's a delay.

I mentioned this a while back and I think it was supposed to have been addressed, but I'm not convinced it has.

Not that I know which is closest to how it actually was, if that's how it is now then all the better.

 

I've hardly used it in FC, maybe partly because of the delay (reduced effectiveness), as likely because the FC engines seem a bit more fragile and I'm throttling down more than I used to. So I'm generally more dynamic with the throttle, which is a good thing I think.

[Cynic_Al]

Like other aspects, throttle control on rotaries has had to be simplified. I'm sure you can guess why.

Some advocate its use in initiating left turns.

If it weren't there, people would bleat about its absence.

 

[LukeFF]

45 minutes ago, HagarTheHorrible said:

In real life, from what I understand, the fuel mixture of a rotary engine has to be adjusted everytime you move the throttle

 

And where exactly have you read / heard that?

 

 

 

[Cynic_Al]

2 hours ago, LukeFF said:

And where exactly have you read / heard that?

 

 

Here for example.

[J2_Trupobaw]

3 hours ago, Cynic_Al said:

 

Some advocate its use in initiating left turns.

.

 

Right turns, too, if you want to make controlled turn rather than ride your engine. And to control thrust in more complicated Dr.I maneuvers where riding full throttle would send plane OOC (throttle is to slow). And to prevent / recover from spin before it settles in Camel (blip, nose down, right the plane, unblip - again, throttle is to slow). Yes, it's slower than in RoF, but still gets the job done.

Generally, throttle is good in situation where one would use throttle if flying inline plane. Blip is good to make rotary as controllable as inline running full throttle.

Edited October 22, 2019 by J2_Trupobaw

[1PL-Husar-1Esk]

In our sims we have simplified rotary engine management , in real there is fuel and air adjusted separately, . One use of blip switch was to reduce power for taxing or landing because most rotary engine were unable to idle at low rpms. And minimum power  which engine do not quit were to much . 

Edited October 22, 2019 by 307_Tomcat

[HagarTheHorrible]

12 hours ago, LukeFF said:

 

And where exactly have you read / heard that?

 

 

 

 

Not were I read about rotary operation originally (still looking for article) but here is another description;

 

"The engine controls comprise 2 levers mounted side by side on a graduated quadrant on the left side of the cockpit. The longer lever (known as the ‘block tube’) is connected to a simple block tube carburettor. This controls the fuel air mixture entering the hollow crankshaft and subsequently reaching the cylinders. However, life is not that simple! There is a second, shorter lever, known as the ‘fine adjustment’ that can further effect the amount of fuel in the mixture at a particular block tube setting. This essentially controls a fuel tap upstream of the block tube carburettor, but a tap that is capable of very fine adjustment. For each block tube setting there is therefore a small range of ‘fine adjustment’ settings over which the engine will still run. These are bounded at one end by the lean cut (too little fuel, engine will cut out) and at the other the rich cut (too much fuel, engine will stop). The latter case is far more serious, as it takes a long time to clear a rich cut with the attendant over fuelling. This would certainly be longer than the time available in a glide if the engine failed below a couple of thousand feet."

 

As you can see, from the description above, blipping is a simpler solution to reducing thrust, when needed, than fannying about with the block tube (BT) and fine adjustment (FA), and with less risk of the engine stopping from a lean or rich cut.

 

If I read this correctly what is implied is, I will use the example of diving down to attack an enemy aircraft in the sim, at the moment I simply reduce throttle to limit engine revs below that that will damage the engine, 1400ish in the Camel, In reality, this closing of the BT, but with the FA still open, would lead to a over rich mixture, too much fuel for the air supply, therby stopping the engine until the flooded engine had cleared. Blipping, on the other hand limits thrust/RPM without the need to control the FA with the retarding of the BT ?

 

Again, not where I originally read about it ,but;

 

"Engine controls

Rotaries were difficult engines to manage. Gross power control was handled via a 'blip switch' on the top of the control stick that switched the ignition on and off. Some types switched the ignition on selected cylinders, but on most engines the switch controlled all cylinders: the engine was either on or off and the aircraft either ran at full power or glided. It was possible to get reduced power settings for landing or to make the engine idle by pulsing the 'blip switch' slowly to give an average output somewhere between an idle and full power. The sound of a rotary flying round the airfield is quite distinctive. As the pilot uses the switch to maintain slow, level flight you hear a BZZZZZZZZZZT............BZZZZZZZZZZT............ noise. A side effect of this power control was that when the aeroplane glided down, coming in to land for instance, oil and fuel was still fed into all the cylinders including those which were not firing. If the engine was off for too long it could be very slow to pick up again. Often as much as 30 seconds was needed to regain full power. This unused fuel was spewed out of the exhaust valves so that it collected in the cowl and on the fuselage as well as oiling up the spark plugs. Meanwhile the pilot got a major dose of castor oil. Switch on again... whoof!!! With any luck, the conflagration would be short-lived. Just as well, because World War I pilots did not wear parachutes.

Another way to incinerate oneself was via an engine back-fire, which was known to start a carburetor fire on occasion. This gave the pilot a case of hot-foot because there was often nothing between his feet and the carburetor.

Although the 'blip switch' was a simple, direct and light weight engine control and adequate for airfield and circuit operation it was tiring to use for formation flying or flying at cruise power for any length of time. None the less, some rotaries just made do with this switch and a fuel lever but others added a power lever in an attempt to make the engine more tractable.

The fuel lever controlled the amount of fuel entering the carburetor: it adjusted the strength of the fuel/air mixture. This is an important control because the fuel flow must be adjusted to suit the day's temperature and humidity as well as the altitude at which the aircraft is flying. An engine will only run if the mixture strength is within a suitable range: if the mixture is too lean or too rich the engine will stop.

Engines that also had a power lever allowed the pilot to adjust the air flow into the carburetor, and hence the power output of the engine when the 'blip switch' was held closed. This made formation flying somewhat easier as well as easing the workload during a reduced power cruise. The range of adjustment was fairly small. Typically the minimum setting reduced the engine speed to just over half the full power value. This was not sufficient to cater for idling or landing approaches, so the 'blip switch' was still needed. The power lever was best thought of as a means of fine tuning the engine's output during normal flight. In any case, for reasons given below, it was not a good idea to fiddle with it when close to the ground.

Each time the power lever was moved the fuel lever needed to be adjusted immediately to keep the fuel/air mixture within operating limits. There was no linkage between these two controls and they did not have a similar effect if moved by the same amount. So, if the pilot needed to alter the power setting he needed to make an immediate and correct change to the fuel setting. If he got it wrong, the engine stopped running though it would still be spinning in the slip stream.

If the power setting had been increased the engine would suffer a 'lean cut' because there was now too much air and not enough fuel entering the engine. The pilot recovered by closing the fuel lever and then slowly re-opening it until the engine restarted. This usually left the plane without power for 5 seconds.

However, if the power lever setting had been reduced the engine would suffer a 'rich cut' because there was too much fuel in the air stream for the mixture to burn. This time the recovery was to immediately close the fuel lever and wait while the engine blew the excess fuel out its exhaust. Once it had dried out the fuel lever was slowly opened until the engine restarted. This process took a minimum of 25 seconds. Hence it not being a good idea to fiddle with the power lever near the ground. If, at low altitude, the pilot suffered a rich cut or, worse, had a rich cut but tried to re-open the fuel lever too soon then he would suddenly find he needed to make an immediate landing without the benefit of an engine. There was also the possibility of an engine fire if there was still a lot of unburnt fuel inside the cowling when the engine started up again."

from;    http://www.gregorie.org/gregories/history/rotary_engines.htm

Edited October 22, 2019 by HagarTheHorrible

[1PL-Husar-1Esk]

1 minute ago, HagarTheHorrible said:

 

Not were I read about rotary operation originally (still looking for article) but here is another description;

 

"The engine controls comprise 2 levers mounted side by side on a graduated quadrant on the left side of the cockpit. The longer lever (known as the ‘block tube’) is connected to a simple block tube carburettor. This controls the fuel air mixture entering the hollow crankshaft and subsequently reaching the cylinders. However, life is not that simple! There is a second, shorter lever, known as the ‘fine adjustment’ that can further effect the amount of fuel in the mixture at a particular block tube setting. This essentially controls a fuel tap upstream of the block tube carburettor, but a tap that is capable of very fine adjustment. For each block tube setting there is therefore a small range of ‘fine adjustment’ settings over which the engine will still run. These are bounded at one end by the lean cut (too little fuel, engine will cut out) and at the other the rich cut (too much fuel, engine will stop). The latter case is far more serious, as it takes a long time to clear a rich cut with the attendant over fuelling. This would certainly be longer than the time available in a glide if the engine failed below a couple of thousand feet."

 

As you can see, from the description above, blipping is a simpler solution to reducing thrust, when needed, than fannying about with the block tube (BT) and fine adjustment (FA), and with less risk of the engine stopping from a lean or rich cut.

You become Human carburettor as one famous vintage aviator said. 

[HagarTheHorrible]

The Sopwith Triplane "Dixie" (Clerget 9j) which crashed a couple of years back, the pilot attributed the cause of the crash to un-noticed loss of height when coming in to land, because he was fiddling with the engine settings.

[Sgt_Joch]

a lot of things are simplified, yes.

 

The blip switch was a holdover from early rotaries that had no throttle. The Camel had both, the throttle and the blip switch. As I understand it, the throttle was the principal means to control RPM and the blip switch was used in landings when you wanted to counteract the torque.

[1PL-Husar-1Esk]

@Chill31 please explain how exactly you  operate rotary engine. 

[Chill31]

My experience running the rotary is still rather limited at this point, since I haven't flown it...

 

Here is a short video I made of how the carburetor works on Le Rhone, Clerget, Oberursel, and Bentley (I'm not 100% about the Bently) engines:

 

I've found that I can leave the minet valve (the fuel fine adjustment) wide open during anything other than low idle settings.  When I run the engine up and lean it out from full rich, I do get more revs, however it still has a lot of power at full rich.  This effect is also present in modern day engines found in light aircraft (lycomings, continentals, etc).

 

The throttle response is much faster than I had anticipated due to my experience with ROF/FC.  The engine will spin up and down faster than you think.  In the following taxi video, I set the minet valve to wide open, full fuel flow, and then I taxied it around.  I wanted to see if I could get a rich cut.  Alas, I could not.  I found that I could taxi successfully (it was a pretty fast taxi though) in that configuration.  That being said, if I had used the fine fuel lever in concert with the throttle, I could have achieved a lower idle speed on the engine.  Based on my experience at this point, I don't think the minet valve is as critical as it has been made out to be.  The engine seems to run well over a range of fuel mixtures, however, there is definitely a "best power" mixture setting.

 

Regarding the "rich cut," I've had rotary pilots tell me it is a myth...BUT in this video, you can definitely see the smoke plume of this engine getting very rich for some reason. As of yet, no one knows why.  I suspect that it is a symptom of having a pressurized fuel tank (most WWI fighters did NOT have a pressurized tank, including the Fokker Dr.I).  At low power, the pressure in the tank is maintained using a hand pump in the cockpit along with slight pressure from the air driven pump mounted in the propeller slipstream.  As you take off, the air driven pump is getting A LOT more air and subsequently adds a lot of pressure to the tank.  The increased tank pressure results in higher fuel flow, to the point it causes a rich cut. If my hypothesis is correct, a rich cut should be an impossibility for most WWI aircraft.

 

The way FC/ROF represents rotary engine control is most flawed by the fact that "idle" on the throttle itself should shut off the engine...?  Other than that,  it is believable.  Some nuances are missing such as how the engine behaves at low power settings on the ground and how the engine works best if you lead an increase in power with opening the minet valve and lead a decrease in power with closing the minet valve (you can see what I mean in my taxi video below.  Listen for the engine run ups to hear the throttle response).  In the video, I only blipped once or twice...the rest I did using the throttle alone.

 

 

So back to the Blip Switch! It is used primarily to get the engine slowed down for landing and during taxi.  In the air, and for dog fighting, I can't see it being all that useful.  Once I fly it, I will have a better idea though...

 

[SeaW0lf]

10 minutes ago, Chill31 said:

So back to the Blip Switch! It is used primarily to get the engine slowed down for landing and during taxi.  In the air, and for dog fighting, I can't see it being all that useful.  Once I fly it, I will have a better idea though...

 

In your experience, does the blip switch has a delay (as in FC) or it cuts the engine instantly (ROF)?

[Chill31]

It is instant.  All the blip switch does is ground the magneto, so the spark doesn't go to the sparkplug.  

Here you can listen to the Fokker D8.  I had to blip it going down hill in order to keep it from getting too fast on the ground.  Not my plane, so I can't afford to bend it up!

 

 

[JGr2/J34b_Matthias]

Nothing like videos to definatively prove a point.  Thanks very much for your insights as always Chill31.

 

 

Edited October 22, 2019 by J5_Matthias

[HagarTheHorrible]

In the video of the Camel, does it force land after the engine loses power (trail of dark exhaust smoke) or is it planned ? 

 

The over rich mixture after take off might be because

 

"I ease back the fine adjustment slightly as the Pup accelerates – as airspeed increases, the propeller unloads, the engine accelerates and centrifugal force enriches the engine. I can’t support a rich cut on take off, so the mixture is leaned during the take off run. "

 

???

Edited October 22, 2019 by HagarTheHorrible

[Chill31]

The Camel was a loss  

https://images.app.goo.gl/aBHUDW7aTGdzzYCp8

 

Where did you find that bit on the engine acceleration?  I wouldn't rule that out, by any means.  I did a static engine run up in the chocks, and I didnt notice any tendency for the engine to enrich or cut out.  I will definitely be keeping an eye out for that phenomenon until I can figure out if it is real or not.

 

 

[HagarTheHorrible]

I found it here:

 

https://haa-uk.aero/document/flight-testing-the-sopwith-pup/

 

On 10/23/2019 at 3:01 AM, Chill31 said:

The Camel was a loss  

https://images.app.goo.gl/aBHUDW7aTGdzzYCp8

 

 

 

 

 

As long as the pilot walks away, ultimately that's all that matters.

 

 

 

Lecture by Andy Sephton, chief pilot and test pilot for the Shuttleworth Collection.  All of the talk is good, but the bit about the Pup and rotary engine flying is in the middle.

 

 here:

https://www.aerosociety.com/news/audio-classic-lecture-series-flying-historical-aircraft-by-andy-sephton/

 

About the speaker:

 

Andy Sephton

Edited October 24, 2019 by HagarTheHorrible

[Arfsix]

On 10/23/2019 at 2:26 AM, HagarTheHorrible said:

 

Lecture by Andy Sephton, chief pilot and test pilot for the Shuttleworth Collection.  All of the talk is good, but the bit about the Pup and rotary engine flying is in the middle.

 

 here:

https://www.aerosociety.com/news/audio-classic-lecture-series-flying-historical-aircraft-by-andy-sephton/

 

 

     Thank you for this post! In sixty years as a pilot, this is the most coherent and complete explanation of the use of throttle (Block Tube), mixture (fine adjustment lever)and Blip Button in controlling the rotary engine I have ever read. I have had many rivet counters (a term meant to be politically incorrect) confirm that a blip button did exist, but none could explain how the button was actually employed.

     Thanks once again.

[1PL-Husar-1Esk]

On 10/23/2019 at 9:26 AM, HagarTheHorrible said:

I found it here:

 

https://haa-uk.aero/document/flight-testing-the-sopwith-pup/

 

 

As long as the pilot walks away, ultimately that's all that matters.

 

 

 

Lecture by Andy Sephton, chief pilot and test pilot for the Shuttleworth Collection.  All of the talk is good, but the bit about the Pup and rotary engine flying is in the middle.

 

 here:

https://www.aerosociety.com/news/audio-classic-lecture-series-flying-historical-aircraft-by-andy-sephton/

 

About the speaker:

 

Andy Sephton

Amazing lecture. Operating rotary sound complicated when describe in words but it's same with one  describe how to ride a bike

As he says you can't fly those rotary aeroplanes as modern ones.

 

I would like to hear Me. Andy Sephton,  full lecture about rotary engines , anyone know if it's available somewhere ?

 

 I wish we could have simulated to the full extent how those engine need to be operated (engine menagment and handling of gyroscopic precession). 

 

Edited October 26, 2019 by 307_Tomcat

[HagarTheHorrible]

Glad you enjoyed it, I'd wondered also, if the lecture at the Suttleworth Collection was available.

[HagarTheHorrible]

More oral stuff by Andy Sephton speaking to the Imperial War Museum.  Three lectures total, last two being of interest to us.

 

Imperial War Museum talks

[HiIIBiIIy]

On 10/22/2019 at 5:01 PM, HagarTheHorrible said:

as airspeed increases, the propeller unloads, the engine accelerates and centrifugal force enriches the engine.

There is something that's bothering me about this statement.

Could someone explain how centrifugal force could enrich the mixture. 

Edited October 28, 2019 by HiIIBiIIy

[unreasonable]

19 hours ago, HiIIBiIIy said:

There is something that's bothering me about this statement.

Could someone explain how centrifugal force could enrich the mixture. 

 

Because the air-fuel mixture is not a solution, but an emulsion. (I think) So the droplets of fuel, suspended in the air, being denser than the air, will end up at the outside of the spinning cylinders. The mix at the centre where it is injected will not alter, but the composition at the outer end of the cylinders will be more enriched the faster you spin. Just like a centrifuge.

 

I was waiting for one of the engineers to comment, but as it has been a while, thought I would volunteer this hypothesis. 

Edited October 29, 2019 by unreasonable

[AndyJWest]

That can't enrich the mixture, Unreasonable. Not unless there is some other exit for air, other than through the cylinders. It's a one-way system, and the fuel/air ratio going into the cylinders has to match the ratio at the carburettor. You suck in X grams of air/fuel mix per second, and blow X grams of exhaust out.

[unreasonable]

It cannot enrich the mixture on average, but it can change the composition of the mixture throughout the length of the cylinder, just as in a centrifuge.  Put the same mixture of anything into two centrifuges running at different speeds and you will get a different distribution of the materials in the two sets of tubes.  Question then is whether this could appear to be "richer" when ignited. If the fuel-air mixture is imperfectly mixed at ignition, combustion may be incomplete even though the total mix is unchanged.

 

Perhaps. 

 

 

 

[HagarTheHorrible]

So, if I get this right.  Fuel is normally less

dense than air, or of similar density, so you get a more, or less, even distribution regardless of centrifugal force.  With the inclusion of castor oil the fuel mixture becomes more dense than the air supporting it and thus is affected by centrifugal force ?

[unreasonable]

6 minutes ago, HagarTheHorrible said:

So, if I get this right.  Fuel is normally less

dense than air, or of similar density, so you get a more, or less, even distribution regardless of centrifugal force.  With the inclusion of castor oil the fuel mixture becomes more dense than the air supporting it and thus is affected by centrifugal force ?

 

Liquid fuel is not less dense than air!  It is much denser, which is why you do not have to hold it down.   Fuel and air mixture consists of droplets of liquid fuel in the air: like your GF's perfume spray.  So you could sort out the liquid fuel from the air in a centrifuge: I am just wondering if that is part of this effect described by Shepton.

 

Densities

Air 1.2 kg/m3

Castor oil 961 kg/m3

Avgas ~750 kg/m3 (varies with grade)

[AndyJWest]

I think you are both making things unnecessarily complicated. The reason the mixture changes as you alter the power setting is that the carburettor doesn't compensate properly for changes in RPM. An ideal carburettor will keep the fuel/air ratio constant under all conditions, but the simple carbs used on rotary engines don't get anywhere close to this. The idea is that the venturi effect as the air is sucked* through the carb draws fuel out of a hole (or multiple holes) in the fuel line. Suck more air through, and the pressure drops, drawing in more fuel. If air and fuel had the common decency to behave like the ideal fluids of physicists' imaginations, it would be all fine and dandy, and the carb would maintain a constant fuel/air ratio over your whole power range. Unfortunately, the fuel in particular is affected by viscosity, and flows slower than it 'should' at low speeds. Which means that you have to richen the mixture at low RPM, and then lean it out as revs go up if you don't want to risk a rich cut. Of course, it's possible to design fancy carbs that do this compensation automatically - or even use fancy electronics and a fuel injector. As Chill31's video above shows though, there isn't anything fancy at all involved on these engines. Just a carb that does little more than mix the fuel with the air, and a couple of valves controlling air and fuel flow. Kermit Weeks discusses this in his videos on his Sopwith Snipe (Bentley engine), and as he puts it 'the pilot is the carburettor'. Move the throttle any distance, and you'll need to tweak the mixture.

 

*Disclaimer. There is no such thing as 'suction' in a gas. At least, not in this context. The system actually relies on atmospheric pressure pushing air in through the carburettor. And presumably on pressure on the fuel line too, though how exactly this is regulated, I'm not sure. 

[unreasonable]

Your explanation - that the fuel flow increases with rpm - may very well be right, and is certainly easy to understand: it is just not the one given by Sephton.  So I was just trying to imagine how centrifugal force as such could have an effect.  Sephton is a pilot not an engine designer, so it is entirely possible that his technical descriptions could sometimes be theoretically wrong while being functionally right. 

 

[HiIIBiIIy]

4 hours ago, unreasonable said:

Because the air-fuel mixture is not a solution, but an emulsion. (I think) So the droplets of fuel, suspended in the air, being denser than the air, will end up at the outside of the spinning cylinders. The mix at the centre where it is injected will not alter, but the composition at the outer end of the cylinders will be more enriched the faster you spin. Just like a centrifuge.

This might be true if the cylinder was just a hollow tube, but it is not, it has a piston compressing the fuel-air mix at the same rate of spin.

[HagarTheHorrible]

9 hours ago, unreasonable said:

 

Liquid fuel is not less dense than air!  It is much denser, which is why you do not have to hold it down.   Fuel and air mixture consists of droplets of liquid fuel in the air: like your GF's perfume spray.  So you could sort out the liquid fuel from the air in a centrifuge: I am just wondering if that is part of this effect described by Shepton.

 

Densities

Air 1.2 kg/m3

Castor oil 961 kg/m3

Avgas ~750 kg/m3 (varies with grade)

 

I think you know what I meant ?, I'm well aware that liquid fuel is denser than air. Fuel molecules, when they vapourize, are presumably of similar density (?) to air (maybe a little heavier), which is why lighting BBQ's and bonfires with petrol is not very clever, unless you want to singe your eyebrows (not that that has ever, ever happened to me, even when lighting a bonfire with a rag on a very long stick) ?.

 

When is the castor oil added, is it mixed with the fuel before it enters the blocktube/carb or separately, later on ?

 

As an aside, when the vapour is compressed in the piston cylinder, presumably the mixture re-liquifies, to a certain extent, not just the fuel but presumably the water vapour in the air as well, but maybe that needs more compression than the fuel vapour ?  Does the water content (humidity) affect combustion, or is it an insignificance by the time it reaches the cylinder head ?

Edited October 29, 2019 by HagarTheHorrible

[Cynic_Al]

11 hours ago, HagarTheHorrible said:

IAs an aside, when the vapour is compressed in the piston cylinder, presumably the mixture re-liquifies, to a certain extent, not just the fuel but presumably the water vapour in the air as well, but maybe that needs more compression than the fuel vapour ?  Does the water content (humidity) affect combustion, or is it an insignificance by the time it reaches the cylinder head ?

 

One way to determine that would be to embed a high-speed video camera in a cylinder wall. While perfectly feasible, it could be a challenging installation on a rotary engine.

[Cynic_Al]

On 10/22/2019 at 11:52 AM, Sgt_Joch said:

a lot of things are simplified, yes.

 

The blip switch was a holdover from early rotaries that had no throttle. The Camel had both, the throttle and the blip switch. As I understand it, the throttle was the principal means to control RPM and the blip switch was used in landings when you wanted to counteract the torque.

 

I'm not sure about a need to counteract torque on landing, but I think the clue is in the name: The term 'blip' as I have always understood and used it, means a momentary opening of the throttle to give a short burst of power/increased RPM. For landing purposes, the throttle on a rotary is far too unresponsive for the purpose, so momentary enabling of the ignition provides the required effect.

[HagarTheHorrible]

Ok, so I've been trying out the Brisfit, with it's inline engine.  Apart from the radiator management, the throttle/mixture routine seems to be much the same as in the rotaries.  Just put it to the start position at switches on and then adjust for maximum revs and then regulate any possible overspeed with the throttle. A bit uninspired, isn't it ?

[Cynic_Al]

35 minutes ago, HagarTheHorrible said:

Ok, so I've been trying out the Brisfit, with it's inline engine.  Apart from the radiator management, the throttle/mixture routine seems to be much the same as in the rotaries.  Just put it to the start position at switches on and then adjust for maximum revs and then regulate any possible overspeed with the throttle. A bit uninspired, isn't it ?

 

Do you want to have to operate the fuel cocks, pump the fuel pressure and vary the ignition timing all manually?  I don't think many would be too inspired by that.

[LukeFF]

4 hours ago, HagarTheHorrible said:

Ok, so I've been trying out the Brisfit, with it's inline engine.  Apart from the radiator management, the throttle/mixture routine seems to be much the same as in the rotaries.  Just put it to the start position at switches on and then adjust for maximum revs and then regulate any possible overspeed with the throttle. A bit uninspired, isn't it ?

 

Yes, it's the same way that it was in ROF, which I know you were around for. So, what's the surprise here? 

[US103_Baer]

7 hours ago, HagarTheHorrible said:

Ok, so I've been trying out the Brisfit, with it's inline engine.  Apart from the radiator management, the throttle/mixture routine seems to be much the same as in the rotaries.  Just put it to the start position at switches on and then adjust for maximum revs and then regulate any possible overspeed with the throttle. A bit uninspired, isn't it ?

 

Try with a Spad in a fight that starts at 4000m and ends at 400m. You'll be quickly dreaming of a dedicated quadrant with independent levers for mixture and radiator.

[unreasonable]

30 minutes ago, US103_Baer said:

 

Try with a Spad in a fight that starts at 4000m and ends at 400m. You'll be quickly dreaming of a dedicated quadrant with independent levers for mixture and radiator.

 

Saitek Pro Flight is inexpensive   Even has coloured knobs so that I can remember which is which.