Keilkraft invader test flight

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VC10 RON
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Joined: 03 Jul 2019, 09:57
Location: Guisborough North Yorks.

Keilkraft invader test flight

Post by VC10 RON » 03 Jul 2019, 10:09

I recently built a KeilKraft invader and converted it for 2 channel radio control using the all moving wing method (twisty wings)

The invader went for its maiden voyage today, All went very well, better than expected.
Location was Marske by the sea headlands. Wind was blowing initially around 9mph decaying to around 6mph.
I launched it off and needed some small trim adjustments, a couple of notches of up and 3 notches of right aileron. I found it very easy and quite docile. Its fairly numb too, not that sensitive considering the amount of movement on the surfaces though I do have a little expo on aileron and elevator. 30 seconds after launching I removed my iPhone from my pocket and decided to video the flight (not an easy task unlocking your iPhone with one hand). Landing was quite straight forward with no nasty surprises. All in all, very pleased with the maiden flight. I would say the wind speed needs to be around 8 to 10mph ideally


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terry white
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Re: Keilkraft invader test flight

Post by terry white » 03 Jul 2019, 20:19

Hi Ron, a very interesting project, I would make a bet here that at least half of us made the F.F. version of this when we were all much,much, younger..Dope and tissue in those days though. My father bless his heart would say that if he thought my latest K.K. model was built better than the last he would buy me my next one. I built most of the K.K.range this way. I was about 10 years old at the time,(Im a young 76 now) :roll: and but for a short time when girls came between me and my models Ive been building them ever since.
Welcome to the forum Ron and please share with us your next build. Regards Terry.

VC10 RON
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Re: Keilkraft invader test flight

Post by VC10 RON » 03 Jul 2019, 20:48

Hi Terry,

Yes, I built one of these as a school boy. Thought it would be interesting to make an RC version given the size of radio gear nowadays. Like you, I can remember my father praising me as I was building the old stick n tissue models, certainly brought back a few memories building this, and I guess that’s what it’s all about eh.

Ron.

john greenfield
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Re: Keilkraft invader test flight

Post by john greenfield » 04 Jul 2019, 07:46

Hi Ron

Could you share with us more details of your all moving wing? What did you use for a pivot, how did you hold the wings onto the pivot and how much throw have you used for pitch and roll. What size servos have you used and did you move the CG forward from the original plan position for more penetration in a wind?
Well done, the model looks very stable in flight.

AEB
AEB = Aeronautical Energiser Bunny (with thanks to CW)

VC10 RON
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Joined: 03 Jul 2019, 09:57
Location: Guisborough North Yorks.

Re: Keilkraft invader test flight

Post by VC10 RON » 04 Jul 2019, 08:30

Hi John,

So, Im using 5mm carbon rod with 5mm internal bore plastic tube, I know this is overkill but it's all I could get hold of at the time, but its a snug fit between the 1/8th sq upper and lower wing spars. The servos are Bluebird 101HV, these were chosen because of their size, speed and ability to handle lipo 2s directly. Radio is Spektrum DX8, though I will be changing over to my converted and completely re-built Skyleader Clubman shortly, just for the more retro feel.
After experimenting with the control surface movements, I've found that 12mm each way measured at the trailing edge root is required. this may surprise most people as been far too much but its definitely needed, Ive also removed the expo and differential on both channels. Even with this amount of movement its quite sedate and not twitchy at all.

Regarding the C of G, Its not actually shown on the plan, A lot of KK early models were like this, so I basically took a guess and set it to 34% chord from leading edge which is right on the main spar. It seems fine where it is though I may move it back slightly as its slightly numb (this may be a good thing), Not really meant to be aerobatic.
The wings are not really held on with anything as the carbon rod goes 6 inches in either side. The servo pushrod sort of holds it in place, I was throwing it around yesterday at Marske sandbanks and it never moved a millimetre.

Penetration seems good as it is, so I'll more than likely leave it as is. Maybe a slight tweak here and there.
Heres a few photos followed by a short video of twisty wings and my converted Skyleader set complete with my own design retail box ( I know, I'm mad). By the way, my Skyleader now has elevon mix built in, so no external mixer is required. Click on images for high res version.

Ron
IMG_0801.jpeg
IMG_0817.jpeg
IMG_0956.jpeg
skyleader.jpg

VC10 RON
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Re: Keilkraft invader test flight

Post by VC10 RON » 06 Jul 2019, 20:54

Heres a short video of the second flight of the Invader, flown today at Marske sandbanks. Lovely conditions. As you can see, its very docile and easy to fly

Ron


john greenfield
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Re: Keilkraft invader test flight

Post by john greenfield » 08 Jul 2019, 14:58

Thanks Ron.

I can see me having a go at this type of control on a vintage model.

AEB
AEB = Aeronautical Energiser Bunny (with thanks to CW)

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Barry_Cole
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Re: Keilkraft invader test flight

Post by Barry_Cole » 08 Jul 2019, 17:19


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