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45cc Black Horse Chipmunk 85" Electric conversion


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Hi Bob, and thanks  yes the thumbs and fingers recovered once they were wrapped around a cup of coffee. Good job really there are some little screws to remove the wings. If we hadn't thawed we would be there still. I must make myself some thumb and index-finger less gloves. I usually just don't fly when its that cold
 
Good luck with the Chippie
 
Cheers
Danny
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Hi Tom, thanks its been a good day. I keep getting invited by Timbo to have a bash at this sloping stuff, but I fear I may not be hardy enough....... perhaps fortified with sufficient sticky buns I may venture forth and chuck some balsa from the hallowed rock. I will keep looking on Ebay for a middle phase or the like.
 
How do you keep your hands warm while flying in the cold Tom? Probably wish i hadn't asked that.........
 
Ross I am glad you enjoyed the thread, I really enjoy the banter that goes on during a build.
 
Cheers
Danny
 
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Thanks Steve, yes I was pretty determined to do this today, I had booked a day off work and had been aiming for today as a target. Hopefully will get some warmer weather soon and I can do Chippy justice, armed next time with at least some thinsulate fingerless gloves. The body was warm the fingers most certainly were not.
 
I don't do cold..........
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Softy mid-southerners eh
Danny ...when you venture up here ( where its actually warmer than most of the rest of the UK presently ) you would be better off chucking a foamy off the rock first.
Plenty of stuff here for you to play with, so you dont really need to bring anything!
Except of course, hot black sweet coffee and the sticky buns
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Well Done Danny
You are very brave going out in that temperature.
Black horse have done a pretty good job getting this one looking near scale.
I did not think the Undercart fairings would last long. On my Airsail Chipmunk i could not believe how far the legs would flex. Even though i cut an angle at the top of the fairings to allow for flexing, on the first landing which was fairly soft (by my standards anyway) they managed to touch the bottom of the wing. I cannot even bend them that far back by hand.
 
Good thread with very good pics, well done.
 
Cheers
 
Mark
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Great thread, v. interesting. It has convinced me that I want a Chipmunk for next year, something I have been contemplating for a while. Just a comment on power and efficiency.  I thought that IC engines are normally quoted in terms of shaft power, i.e the power that goes into the prop, so the 2hp that has been mentioned is comparable with 1500 @85% = 1275 watts.  The efficiency of a bigger slower turning prop on the electric (and the reason for using gearboxes on early motors) will probably make up the difference. I am not disputing a low overall efficiency for IC engines, just that they are rated (I believe) in a different manner, due to the difficulty of measuring the energy input, other than as fuel consumption.
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Thx Timbo very generous offer, really must make time to take you up on that
 
Hi Mark, glad you enjoyed reading about Chippy. I was a little surprised the fairings broke so soon, especially after that peach of a landing  ah well.
 
Hi Chris i think you are probably closer to the truth than my ramblings, but as ball park figures go it proved to be about right. The prop on the full size Chippy is I believe 6'6" or 78" at 1/5 it should be around 15 1/2" not really big enough to benefit from the higher  torque and larger prop advanatges  associated with electric. So with just a 15 x 10 prop I have had to use higher rpm to get the power and thrust. But you are right an electric motor tends to be expressed in input power and not output which an IC motor would be. Anyway it flew happily on 1200 watts (input) will try some simple aeros on the next flight and see if there is indeed enough for loops
 
Thanks David, yes it is a bit floaty, but that is a lot of wing area for a 12lb model, imagine what will happen if I lower the flaps? I flew it much to quickly, but as I said previously I wanted to be safe while I was trimming. Looking at the video afterwards shows how much it got swept downwind in the turns. I think it was windier higher up than I first thought.
 
Thinking about the undercarriage, for the fairings to survive the oleos need to be mounted really rigidly, attaching them to piano wire torque arms means they will spring. great for shock absorbing, but the fairings will not survive the leg springing backwards and forwards into it. A simple solution would be to mount the fairings on the oleos, but you would have to leave a gap at the wing joint, or it would damage the wing skin with the movement.
 
Cheers
Danny
 
 
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  • 1 month later...
just thought i would give an update on the second flight.
 
Got the model trimmed out and enjoyed a 12 minute flight, I consumed just under 5000mAh (out of 10000) so the model should be good for 20 minutes. It looped but only just. I need to get a bit more time in on it, but it looks great in the air.
 
It drew 71A max according to the Jeti.
 
Cheers
Danny
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  • 4 months later...
well am getting to grips with the Chippy and it really is a lovely flyer touch and goes are great fun and it will do lovely stall turns and side slip approaches. It does nice loops too but  it needs a bit of a dive first to make them big enough to look realistic.
 
My thanks to Chris for these photos, thanks mate
 

In formation with a YT Spit that was just heading out on a sortie
 

Must refit the leg covers really takes the edge of this looking pretty realistic don't you think?
 



Anyway it will be at the RCM&E 50th party if you want to see one up close
 
Cheers
Danny
 
 
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  • 1 year later...
This thread being a year old might have self closed but I've just bought one of these Chippies and it has no thrust line centre markings so that the engine mount can be positioned correctly. The instructions (such as they are!) show the usual cross lines but the model has none. Ripmax have, so far, failed to help. can any one else say where they should be? is the tank hole centered on the thrust line?
Hope someone knows!
Pete
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Hi Peter, I have slept since I built mine, but looking at the pictures on the thread it looks as though I centred on the fuel tank hole. However as you will see that did not produce the correct angles an I had to pack the motor mount with a washer or two.
 



Hope this helps?
 
Cheers
Danny
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Thanks, Danny, you have confirmed what I found in the end by trial and error. Your picture with the offset shaft was my first discovery, except that I also had a severe offset to starboard as well!. I've added some pics to show the end result and you'll see that I made a box to take up the extra distance needed to get the prop out front and I had to reposition it twice to find the answer. Looking at the so-called instructions, there are some cross lines shown which indicate the need for height although they aren't dimensioned and they appear to go through the top of the hole - but they don't show the off-set to port. Anyway, I think you'll agree that the final result looks promising! Thank for you interest, it was good to have the encouragement of your findings.
 
all the best
Pete
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I was looking at the pilots yesterday and if they're heavy as well as naff then they ought to go. How did you get them out, Danny, did you cut the complete floor away?
 
Looks like a good day for building where I am - absolutely chucking it down!
 
Cheers
Pete
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Posted by Danny Fenton on 14/07/2011 10:36:57:
Well done Pete, that looks super. The cylinder showing through the front of the cowl is great too. I keep meaning to make a dummy cylinder but so far I haven't got around to it
 
The oversized pilot figures in the canopy BTW weighed a lb on their own!!
 
Cheers
Danny
 
Heavy and naff looking but were they further from scale than the one you've fitted - which has a really good look to it in the landing picture but seems a little undersized to me!
 
Take a look at this picture - the pilots seem much closer in size to your originals to me.
 
I'm being picky here - you've made a lovely job of your Chippy but so few models seem to have accurately scaled pilots and to me it can spoil the scale effect very easily. The majority of pilots fitted are undersized - we tend to overestimate the size of the aircraft we're modelling.
 
Does anyone know where I can get a nice full length 1/4 scale civilian pilot for my Cub?  The one I've got (allegedly 1/4 scale from Hangar 9 and sold for their version) would stand a bare 5 feet tall if scaled up - just acceptable but I'd like a more normal sized occupant!
 
P.S. The range of "dummy cylinders" complete with a strategically positioned pushrod tube that OS, SC, ASP, Magnum etc. market give a nice sound to the model as well!!! 

Edited By Martin Harris on 16/07/2011 11:47:35

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If you scale the wing-span, 85" - 34' 4" (412") = 4.84 so closer to 1/5 scale than quarter. But you are right it isn't perfect. Those bone domes the RAF guys wear are enormous though. My guy is wearing just a smile

The canopy was removed, and the floor also removed. The dash boards were then set back and replaced/detailed. The combing was also altered slightly. The rod/tube that runs from the top of the canopy frame to the base was also added. I should have mounted a dummy compass on this tube, but thought I was getting carried away.

All the decals were my own based on a very specific chippy, the matt nose section was all resprayed also.

You wont get me putting an unreliable IC in one of my models I am afraid, I watched a lovely Spit re-kit itself today at Cosford due to a dodgey IC. I will turn a dummy cylinder on the lathe when i get some time.

You will really enjoy this one I am sure, its a lovely flier

Cheers
Danny
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I see what you mean Danny - the angle the photo is taken at makes a lot of difference. At the end of the day, scale modelling is all about an illusion anyway and if it looks right in the flesh (plastic?) then that's the important thing.
 
If it's any help, I'd imagine that there's nothing stopping the full size flying without the fairings...

Edited By Martin Harris on 16/07/2011 22:51:32

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