GWS corsair fu4 maiden, cause for concern!

[Nick Farrow]

Hi,

 

I know it was under £30, but I spent time and effort in putting this togther, with a strengthening rod in the wing, covering with tissue and poly vanish to add strength and give a decent suface to paint it. Having done all this its taken me 3 months+ to pick up enough courage to fly it.

 

SO out it came yesterday lunchtime in field with growing vegetation to help wih any disasters. It launched fine and true with plentty of power on tap, the cog seemed fine as it went as it on rails. I had reduced the rates so it was really manageble. After 7 minutes of circuits and gentle rolls loops, I dived into a tighter loop to loose height for landing. Coming out of the loop I lost alot of control, I was convinced that the battery had come loose and the cog was well back as it seeemed to sit on its tail and looked like it was about to fall out of the sky I gave it half throttle to try and pull it gently up but it just stalled into the ground from about 15 feet. Given it was just eps foam I feared the worst. However I need not have worried the strengthening rod and doped tissue has stopped the wing exploding as it meet the ground.

 

I carefully checked it over and no control had come loose, the battery had not moved, the cog was fine and I was mystified. After 5 mintues of further checking I plucked up enough courage and gave it aother quick flight. It was fine and I brought it back for a landing over soft vegetation at a slow speed and there was not a hint of a stall.

 

The rx is a corona 35mhz dsp which had proved faultless in all my models, so I dont think is was glitching, I did have partial control so I'm happy this was not the case.

 

This leaves a stall or something else. I'm not vastly expeienced but I fly a gws p40 that does has stall tendencies so I tend to fly with this in mind and keep the speedup. Particularly as I was coming out of a loop gently the air speed should be fine.

 

The only other thing was some sort of esc issue, but the controls were fine when I check about 30 seconds after is crashed.

 

I hate having models that you dont 'trust' or know what happened .

 

Any ideas welcome.

 

Thanks

 

nick

 

[Martin Harris - Moderator]

First thought is to ask whether you remember what you were doing with the elevator while it was misbehaving.  As you're probably aware, tightening the loop also increases the G load meaning that a stall becomes more likely and if you were subconciously holding in up elevator to keep away from the ground it may have remained stalled until the ground jumped up and hit it!

 

Otherwise, is there any possibility that the battery could have moved and been jarred back into place in the arrival?

[Former Member]

[This posting has been removed]

[Nick Farrow]

Hi,

 

Thanks for  the replies.

 

It all happened a bit quick, I dived into the loop and flattened it as it came out, given the reduced rates I dont think I killed the speed by pulling up too much. I do remember feeling that the control was not there and remembered seeing that It had pulled up level but was sitting on its tail with the wings rocking. At this point I applied the throttle, but it was a bit tentative as I was convinced something was loose. Either the throttle was not enough or it had not fired up as I saw it roll into the ground.

 

The wings are bolted in and still solid after it dumped, although cracked on the right wing under the tissue, and the battery is held forward to the cog point by a felcro strip and so I dont think this had moved back and forth.

 

I was just hoping someone would some how solve the mystery!

 

It could just be a stall but it really did behave like a very tail haevy model.

 

Thanks

[Martin Harris - Moderator]

Possible blanketing of the elevator by the wing? (remember the deep stall experienced by Papa India at Staines?)

 

Not terribly likely on a conventional and proven layout but a good power to weight ratio should allow you to pull out of it if it happens again.

[Simon Chaddock]

" I dived into a tighter loop to loose height for landing" does not sound like the sort of thing I would recommend particularly on a maiden flight.

 

My suggestion would be to do exactly the same thing again, but higher, to see if it a real characteristic of the plane or simply finger trouble.

Then try to get the plane to do what it actually did (again higher) to see what control inputs are required to make it do it and how quickly it recovers.

 

I hope this helps.

[Steve W-O]

Effectively your angle of attack was much higher than normal as you had just come out of a loop, so it stalled. From your description, it doesn't sound anything more sinister.

[Nick Farrow]

I guess I'll go for the stall, it just seemed so unlikely as the rest of the flight was predicatable, docile and on rails. Doing it again higher with tight loops seems a good plan to prove it.

 

Thanks

[ken anderson.]

hello nick--i've been flying a one of these for the past 3/4 year's....now and then mine will catch me out...if i get it wrong---in the past i thought all sort's of thing's were wrong...radio/glitch's etc.......but i think it's the model's flying characteristic's(think that's how you spell it)....not helped by the fact it's dark colour scheme...makes it look like a silouette....

 

           ken anderson  ne....1

 

 ps-i'm on to corsair no 3.....

[Nick Farrow]

Hi Ken,

 

What improvments have you made and what power setup do yo use?

 

I suppose I was a bit stupid to think I had it characterised after a couple of circuits

 

Cant wait to give it another go

 

nick

[ken anderson.]

hello nick-at the end of the day the GWS foammies are really-throw away model's...a bit of fun for not a lot of dosh....i've had various set up's in mine and the current one(pun..current one/electric) has a 80watt bell motor/outrunner..and a 3s 1000 m/amp 15c lipo..which give's aprox 10 min's of flying-i also have a servo in each wing...i have mine slightly nose heavy..and it's ok.....tail heavy and it's extremely twitchy......check out my photo's-it's in there...

 

             ken anderson   ne..1.

[Nick Farrow]

Just found the cause

 I was changing the bat posn and fired it up to check all was well when it suddenly went totally dead stick. After much severe waggling of wiring if found the aileron plug was not fully home on the rx pins, The cable onto the plug stuck further back in the fuz making the connection tentative. When it 'made' the connection the surge of the 2 servos seemed to reboot the ESC, or brown it out for a few seconds

 

Nice to have found it!