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Should I sell my DH88 Comet?


Chris Bott - Moderator
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Chris, dont you worry about that flying style.

Getting that final aproach on models i learnt on gliders, does this equate to powered? maybe.

On those speedy types, landing is decidedly faster as in real life, but changes have been made by modellers to reduce this. have i lost models with too steep a banking roll? Yes.

Too much rudder? yes,

too much landing speed? no . but damage wa s part of the result. so flying our models like the real thing rather than darting all over the sky and expecting a slow walking pace when landing is one of those mixes that conflict at times.

RE. bounce boUNCE CRUNCH.

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  • 2 months later...
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Thanks Peter, that is something to consider. Although it's also been suggested to me that washout effectively reduces lift which means the model has to fly even faster.

I think flying this model just requires confidence, which I've been slowly building on other models for a while now.

Danny, Bulldog is indeed the DH88 in the film.

buldog dh88.jpg

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Hi Chris

Yes, washout will reduce the total amount of lift but it will be a trade off where you will avoid a tip stall as the centre section will stall first. So provide your approach speed has a decent margin over your stalling speed you will be fine. Obviously, carry out a check of stalling speed at height and do several practice approaches. Pick a day with a bit of breeze and your ground speed will be signficantly reduced so the higher airspeed won't look so ....high!

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  • 1 month later...

Thanks to all the encouragement on this thread, an extremely enjoyable afternoons flying was had today.

Thanks everyone for the push I needed.

It turns out that all the flying I've done this summer has massively boosted my confidence, and leaving this model for months on end, has meant I've forgotten al the hours spent on it.

So, today, without apprehension, some great flights were really enjoyed. Great big turns with lots of power on, dives into fast low passes and even a loop .

Landings are still interesting. Half flap got it down where I wanted but we still had a big bounce. Full flap meant a nice steep approach was achieved without building up speed. But now, I held off too long, trying to avoid the bounce. A tip stall at about a foot up just reminded me that the tail I was holding does indeed belong to a tiger. What a great Tiger to fly though, with the right flying style, she's a real pussycat.

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I was lucky enough to be flying with Chris today and I have seen every previous flight of the DH88. I must say Chris was totally relaxed with the model today. It will bite sure, but it is nothing to be really frightened off and Chris flew it really well. Wish the weather had been better at the RCM&E do, perhaps more could have enjoyed seeing it fly.

Sell it.....I think not... I suggest you get some retracts Chris teeth 2

Cheers

Danny

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I'm always interested in the tip stall/ wash-out issue and the "quick-fix" of a bit of upwards reflex on the aileron is an attractive idea for a wing that is already built. As far as the conclusion that there will be some loss of lift, while that's my first reaction, I'm starting to think that it might not be much of a problem. It's doing the same as wash-out in the sense of reducing the effective angle of incidence of the whole wing, but concentrated in the outer wing. This should mean that in trimming for level flight, the model will compensate by adopting a slightly greater angle of incidence overall and more or less cancel out the difference. Does that make sense? In practice that would mean a slight difference in the elevator trim so the nett effect would be a small increase in drag rather than a loss of lift, but in practice it might hardly be noticeable. Of course this might be a load of waffle but I had a late night!

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Thanks for the comments every one. Much appreciated.

Colin I did think long and hard about slight up ailerons, and I agree with your conclusions. However, the effect of reduced lift must be very similar to reducing wing area. If the wing area were reduced, the wing loading would be higher. Higher wing loadings mean a higher minimum speed.

I've never quite understood why the pointy wing tip plan form is so prone to tip stalling. (I know all too well that it is though). So the decision was made to leave it as is, and do a better job of flying the model.

So, Danny (thanks for the moral support by the way, and for some of the pics. thanks to Nick Green for the others) what are my options on retracts. ASM used to sell a set of air retracts for this model which had the cylinder facing on the opposite direction.

What I'm wondering is: Are there any differences between units that retracts sideways, and those that retract backwards? Particularly in respect of the direction of landing loads.

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