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Author Topic: Hawker Tempest II, 1/24 scale rubber power.  (Read 10523 times)
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strat-o
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« Reply #175 on: March 04, 2020, 09:18:48 AM »

What about wing reflex?  Could you add it without making the appearance too odd to your eye?  Reflex should reduce the load on the tail.  You could test this simply, I think, by adding a full-span gurney flap to the top trailing edge and retrim.  If it works you could then decide how to make it look right.

Marlin
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tom arnold
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« Reply #176 on: March 04, 2020, 07:12:48 PM »

I would not give up on the Tempest as it is a calm weather flyer, pendulum or not. Rough air never gives an honest appraisal of any gliding or test flights.
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OZPAF
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« Reply #177 on: March 04, 2020, 09:35:51 PM »

That is a bit disappointing Stephen. Looking at the tail size - it should have had more pitch stability. I'm afraid that leaves the most likely suspect - at least in my eyes as the wing airfoil. It's possible that the airfoil is operating at a point where the slightest changes in flight speed will dramatically affect it's lift.
Was the model flying slower with this prop than with the older one.

This makes it very hard for you to maintain the degree of scale appearance that you strive for. A larger model would help with these airfoil problems - however you are after a small field flyer.

I remember using Martin Presnell invigorators on a thick foam wing semi scale Zero(rubber powered) some years ago. It was around 20" WS and the invigorators did improve it. It certainly doesn't look scale - but it may help to verify if that is the problem.

John
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rgroener
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« Reply #178 on: March 05, 2020, 01:34:32 AM »

Stephen, a stunning build as always. I hope you can sort out the aerodynamic troubles.
Roman
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Prosper
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« Reply #179 on: March 05, 2020, 06:52:05 AM »

Thanks for the kind comments and suggestions folks. That's a smart idea Marlin, I'll try the 'Gurney reflex' test sometime. Because the Tempest II model had the same issues though I have a feeling of throwing good money after  a dead horse etc, etc. The model has to compete for limited building time, with other projects that [cough] seem to have [ahem] more potential. My gamble was that the Tempest V was a better prospect than the Mk.II but that seems not to be so. I think that there's something fundamental to this specific propeller/wing/tail combo that's mucking things up.

Tom, I know you're right about interpreting flights. I've told myself many many times in the past that I'd be wasting my time trying to test fly such-and-such in such-and-such a wind. In this case I took what chance I had, after weeks of very windy weather.

John, I had to look up Martin [Martyn?] Presnell. Trip strips? I'm glad to hear that they work even on small models. Another thing to try, tho' I don't expect I'd want them on a scale model.

Stephen.
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