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Ripmax Spitfire EP


Kelly
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I use my right hand and its more of a gentle push really. depending on how much power you have available she should pull away quite nicely. Mine tends to drop away to the left slightly but its all very gradual and you have time to correct. I have some expo dialled in to soften the controls a bit. 
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I was asked for details of the lightweight dolly that we use with the Spitfire and other funfighter type models. It's been posted before but it won't hurt to have some pictures and details here.
 
The dolly is made from plastic tubes and mouldings from a broken Wendy house, with lightweight foam wheels on a piano wire axle, some model supports from a dense foam, cable tied to the frame and a tailwheel from the model shop.
 
http://www.modelflying.co.uk/members/albums/



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Maidened mine this morning, quite punch gusty on a 13-15mph base airspeed, but hey, the next chance to try it out might be a week away, and it is intended for PSS slope use as well as flat field.
 
See my post of 8/6 for full tech info, but I'm only using a
 

Special Power A2814- 6 40A 1410Kv SP Brushless Outrunner Motor (with a 9x5 folding prop)

 
A massive £14 to buy!. 
 
Low rates used, set to instructions settings.
 
Solo, so had to be self launch.  Held in left hand using the under wing handholds, I revved the motor to a bit more than half throttle using my mouth on the throttle stick, holding the Tx and with right thumb on the A/E stick, which is how I'm used to self launching, at which point I was hanging onto the plane so hard the walls of the finger holes started to crack like they were about to give, so a quick chuck, ready or not, and away.
 
Needed three clicks of right Aileron and one click of right Rudder (that's the most out of trim any plane I have ever made has been!).
 
Quickly found that despite the wind it would fly warbird style into the wind on a tiny bit over half throttle.
 
 Crosswind, slowed up, it was getting knocked around a bit, but never really scary.
 
Switched Ailerons to high rates as std not responsive enough. (High being set plus and minus 20mm, only 20% Expo, as I like nervous), but elevator and rudder remained as per instructions for now.
 
Flew around a bit, couple of loops, a few split S's, went high and proved it'd hover into the wind on minimal throttle, one fast pass, one missed approach to get the feel and a landing centre patch.
 
Just finished recharging the 2300mAh 30-40C Tipple while writing this, only used 556mAh!!!
 
That'll do for starters!! 
 
 
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Inspected last night and the fingerholds were cracking, so have impact glued in a very thin ply load spreader.
 
Unusually, managed to get the RC Kids Club stuff charged and ready in time, so managed to have another flight this morning.
 
As I left home was treated to a close up view of a real Spitfire with two Eurofighters tagging along in diamond, nice, but the poor Merlin got drowned out!! (Biggin Hill Airshow prep I assume).
 
Bit less wind than yesterday, but now skewed off a line of trees, so irregular down wash over patch.
 
No change to set up, launched on 3/4 throttle, immediate cut back, and flew one battery more or less like a warbird, nice huge loops and warbird rolls and reversals.  Most flying on just under half throttle.
 
Second flight, decided to explore what performance IS available (rather than what it NEEDS to fly "scale" like). Opened it up and nose vertical.........Strewth.........OK, unlimited vertical available on 3/4 throttle then, with rocket lift on full. On high rates the roll rate is very quick and of course much more axial.  All this looks totally wrong of course, but just testing what's there in the event of need (honest!!).
 
Two "floater" landings, really easy.
 
Finished the second flight with a combination ending of  mixed "warbird" and "loony", after landing the motor was warm, the ESC and battery JUST having the chill off them.
 
So, there you go, a cheap, powerful and light budget set up:-
 
SP 2814 - 6 Motor, 9x5 Folding Prop, 50mm vented Spinner
 
Hobby Wing 40A ESC (BEC)
 
Loong Max Tipple 30C 2300mAh 3S
 
I used SuperTec Parkflyer "Fast" servos. 
 
 
 
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Nice one Dave - youre using a higher Kv motor than me - which is fine, but I have just got into the habit over the years of using larger slower props
I re-inforced all along the bottom with F/G as I slope mine too - this re-inforcing also extends around the hand holds.
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Posted by Tim Mackey - Administrator on 18/06/2010 14:15:45:
Nice one Dave - youre using a higher Kv motor than me - which is fine, but I have just got into the habit over the years of using larger slower props
I re-inforced all along the bottom with F/G as I slope mine too - this re-inforcing also extends around the hand holds.
 
 
 
Yes, I use on the smaller side because I started with EP late, and with high kV motored fast wings, whereas a 9" diameter prop dangling off a 50mm spinner seems big to me!!  .
 
I also have found that, for me at least, the precession (torque) effect is less with smaller faster spinning props.
 
I have so far resisted the belly protection route. Probably regret it, but most places where I would slope it have fairly soft grass landing zones. 
 
I only paid £30 for the unstarted ARTF, so am well pleased with it. 
 
About the same time I was given a Flying Legends Mustang to repair and fly, now THAT is one nasty horrible waste of money, which I am SO glad I didn't spend money on.  I had thoughts of maybe using it for PSS.................I think it would need a hurricane with 45 degree lift in it................a brick would handle better.
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BTW it was neutral in the dive tests today, and flew inverted (sorry should have issued a non-scale alert first!!) with almost no "down" applied, with the CG at 70mm.
 
Seems remarkably vice free for a "Spitfire" shape, they did a good job in design.  I'm impressed....and that's not common!!!
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Second flight of the day with my Spitfire today, cruising on half throttle about to turn back downwind and high over trees it stuttered with a thump and lost thrust..........and I could just make out the cowl was at a drunken angle.  Got it back towards the strip avoiding trees, various, but no chance of turning back upwind or reaching the strip slow enough to land downwind.  Gliding low too fast past the strip, I was forced to land the last ten feet altitude downwind in hay stubble out of sight down a slope.
 
Got it down with no more damage. Either the folding prop failed on one blade and the out of balance forces ripped the mounting out, or the mounting failed, taking one blade off against the cowl...hard to tell.
 
The mounting had not failed at my mod to shorten it for the rear mounted brushless, this and it's glassed reinforcing was intact, but the front motor plate itself had disintegrated, leaving the central cross still firmly attached to the motor.
 
SIGH.................
 
Cowl seems an easy enough repair, albeit it won't get the sky band back, motor seems OK, only the front end frame and mounting needs a complete redesign!  
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  • 3 weeks later...
OK Update.................
 
It's repaired and ready to fly again.
 
The problem was not joints per se, I'd beefed up the glue around all mount joints...........it was delamination of the lite ply motor mount.  Large areas of the three ply were three times one ply............pretty poor, really!!!
 
I have had to repair the cowl as Ripmax, while listing the cowl as a spare, don't have any nor any indication (to trade) of when they might get any .
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  • 2 weeks later...
Having read this thread with great interest I've re-fitted my spitfire,I used to fly it unsuccessfully on old brushed motor and horrible heavy batteries, so thought I'd re-work it with the new stuff I have in other models...
 
However...
 
I'm no-where near the weight, (983g or 2lb 2.7oz) and can't balance on a CofG 75mm back from the leading edge... have to add 100g up front...??
 
From everything I've read here lighter is better, but it's got to balance... my set up is very similar to those here - out-runner, 35amp SC, 2500 LiPo, so if anything quite heavy up front...
 
Has anyone any tips on lightening the tail (so saving the extra 100g in the nose)?
 
I can't see how I can be so far out everyone else... 
 
Or should I just add the weight?
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Posted by Simon Day on 21/07/2010 14:10:17:
Having read this thread with great interest I've re-fitted my spitfire,I used to fly it unsuccessfully on old brushed motor and horrible heavy batteries, so thought I'd re-work it with the new stuff I have in other models...
 
However...
 
I'm no-where near the weight, (983g or 2lb 2.7oz) and can't balance on a CofG 75mm back from the leading edge... have to add 100g up front...??
 
From everything I've read here lighter is better, but it's got to balance... my set up is very similar to those here - out-runner, 35amp SC, 2500 LiPo, so if anything quite heavy up front...
 
Has anyone any tips on lightening the tail (so saving the extra 100g in the nose)?
 
I can't see how I can be so far out everyone else... 
 
Or should I just add the weight?

Fit something like a 3000mah 3s1p or, as on ours, a 4500mah 3s1p and she'll balance just fine. better to carry another 2000mah of capacity than 100g of dead weight.

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