Fokker D.VII in action!

[Holtzauge]

For those who have not yet taken the plunge and gotten Il-2 Sturmovik's Flying Circus 1 & 2 yet, check out this Fokker D.VII "commercial" and how fun flying WW1 kites is!

 

Granted, this is a Fokker D.VII replica powered by 200 hp Ranger and not a Mercedes engine, but the sound is still awesome! 

 

Too bad the guns are still missing and that the pilot has no spiffy uniform like @Chill31, but he remembered his white scarf anyway! 

 

 

 

 

 

 

Edited June 6, 2023 by Holtzauge

[Knarley-Bob]

That WAS cool    

 

 

KB

[RoterTod]

very nice wish it was me.............

[ZachariasX]

It‘s amazing how little rudder input he needs. Fokker really made ailerons that work as we expect them today. Cool vid!

[Holtzauge]

6 hours ago, ZachariasX said:

It‘s amazing how little rudder input he needs. Fokker really made ailerons that work as we expect them today. Cool vid!

 

Yes, and also note how crisp it handles: No wobble at all! Almost like it was on rails! Totally unrealistic flight model! 

 

On a more serious note: I have been helping the owner Jeff Brooks with performance calculations: He gets the required revs 2450 rpm that should give 200 hp from his Ranger yet only does 102 mph and climbs at 830 fpm at SL. From 200 hp I would expect 113 mph and 1225 fpm at SL. No idea why there is such a big difference. And if you plot his 830 fpm on a climb rate versus W/P chart he is not on the line but way under.

 

However, He does say that his engine runs hot and I've asked him about the engine conditions since I suspect he is not getting 200 hp out of it and that the "missing" hp are maybe being delivered as friction instead. This is since he has already renovated the "top" of the engine so the compression should be OK. However, apparently the bearings on the crankshaft are an unknown entity but I'm not an engine expert so I have no idea if that could have an impact......

 

Edited June 7, 2023 by Holtzauge

[ZachariasX]

43 minutes ago, Holtzauge said:

He gets the required revs 2450 rpm that should give 200 hp from his Ranger yet only does 102 mph

He has 2450 rpm in flight while doing 102 mph? You know what kind of propeller he used? (Aww.. there we are again, a propeller discussion ?)

 

If he has something like they put on an Continantal O-300 (like on a C172), then that would be a propeller for about 165 hp output maximum. If that was the case, I could imagine why the aircraft is "underpropped" and does not make most of its engine.

 

As an example, modern propellers are tuned for faster aircraft, see here:

https://www.sensenich.com/shop/aircraft/74dr/

 

The 74 inch prop for an O-300 is made for some 125 - 165 hp output, but then for a flight speed of 120 - 170 mph!

If he used the larger 76 inch prop for the Lycoming O-360, he's still have a prop optimized for 120 - 170 mph, while being suited for 180 hp (which probably is near his actual outout).

 

If the above speculation were in anyway resembling the actual situation, then I wouldn't be surprised if he had 2450 rpm on the tach while missing 10 % airspeed. It's just not efficient dragging something as aerodynamic as a Billy-shelf through the air by something meant to tow something with a minimum of aerodynamic sophistication. I'd go larger and flatter as a choice for prop.

[Holtzauge]

39 minutes ago, ZachariasX said:

He has 2450 rpm in flight while doing 102 mph? You know what kind of propeller he used? (Aww.. there we are again, a propeller discussion ?)

 

If he has something like they put on an Continantal O-300 (like on a C172), then that would be a propeller for about 165 hp output maximum. If that was the case, I could imagine why the aircraft is "underpropped" and does not make most of its engine.

 

As an example, modern propellers are tuned for faster aircraft, see here:

https://www.sensenich.com/shop/aircraft/74dr/

 

The 74 inch prop for an O-300 is made for some 125 - 165 hp output, but then for a flight speed of 120 - 170 mph!

If he used the larger 76 inch prop for the Lycoming O-360, he's still have a prop optimized for 120 - 170 mph, while being suited for 180 hp (which probably is near his actual outout).

 

If the above speculation were in anyway resembling the actual situation, then I wouldn't be surprised if he had 2450 rpm on the tach while missing 10 % airspeed. It's just not efficient dragging something as aerodynamic as a Billy-shelf through the air by something meant to tow something with a minimum of aerodynamic sophistication. I'd go larger and flatter as a choice for prop.

 

For the 82x47" with 2450 rpm the speed was 102 mph. For the 80x48" and 2350 rpm it was 109. So how does that fit the pitch/rpm based estimates? 

 

But do try and plot climb rate as a function of W/P and you will see that they generally fall on a line. Jeff's Fokker D.VII weights about 2000 lb and the Ranger is supposed to give 200 hp at 2400-2450 rpm. The 82 x 47" got 2250 on the ground, 2350 during climb-out and 2450 in straight and level flight. And 830 fpm falls quite under the expected climb rate.....

[ZachariasX]

25 minutes ago, Holtzauge said:

So how does that fit the pitch/rpm based estimates? 

? Depends on his gearing.

 

But that size 82x47" makes sense (especailly regarding his static run) and it is odd that he comes short of the numbers.

 

But I can't help noticing that with 2% pitch increase, he gets 6% in added speed.

(Not 6%, forgot the rpms but is is still a tad more. Pathological.)

 

Edited June 7, 2023 by ZachariasX

[Holtzauge]

12 minutes ago, ZachariasX said:

? Depends on his gearing.

 

But that size 82x47" makes sense (especailly regarding his static run) and it is odd that he comes short of the numbers.

 

But I can't help noticing that with 2% pitch increase, he gets 6% in added speed.

(Not 6%, forgot the rpms but is is still a tad more. Pathological.)

 

 

Yes, it is strange isn't it? But again, the big thing that bugs me is that the climb rate for that W/P quotient seems way too low. So I still suspect he is not getting the full power out of the engine.

[ZachariasX]

13 minutes ago, Holtzauge said:

So I still suspect he is not getting the full power out of the engine.

Internal combustion engines on a dyno often leave one disapointed... even when they don't blow up.

[Cynic_Al]

Do we know how the self-levelling of the camera is achieved? Is it a built-in feature of the camera or is it the mounting?

[=IRFC=Gascan]

10 hours ago, Cynic_Al said:

Do we know how the self-levelling of the camera is achieved? Is it a built-in feature of the camera or is it the mounting?

A lot of go-pro, action cams, and similar, like the Insta-360, have a leveling feature. Its just software processing on the camera, looking for things that could indicate a horizon or even just stabilizing the background. I use such a camera on my model battleship to record the battles. On some ponds it struggles to find the horizon, and you can see when it activates and when it loses track.