Alex7403

Hello,

This Chipmunk will be powered by OS 91 FX, a little bit too big but this is what I have available, I was thinking tower hobbies 75 but its out of stock.

Will be using Elmer’s pro wood glue and epoxy most of the build, the idea is to minimize the use of CA.

This is a cold turkey build (again) so I’m trying to keep my head busy.

I’m planning some simple mods here:
• One servo per aileron in wing – no bellcrank
• Fiberglass cowl and wheel pants
• Balsa belly pan on bottom wing instead of the supplied one from plastic
• 4” fiberglass tape on wing center with no major cuts in wing center
• Plywood chin with T-nuts ready for main gear on the fuselage in case the in wings LG brackets will give up
• Reinforcing the landing gear inside the wings
• Antenna tube for 72 MHz receiver just to have it in and to get a new 2.4 GHz system


I need pictures of good setup of aileron servos in wings and how to reinforce the landing gear in wings.

So we begin,
Day 1: Stab, fin, rudder, elevator

MinnFlyer

My Feedback: (4)

Alex, I'll work up a diagram of the servos for you, but refresh my memory. Does that wing have cap strips on the ribs?

Archie League

I would have agreed that a 90 would be too much engine until I saw one with a 120Surpasson it. It flew like a pattern ship. I have a OS 75 on a 7 lbs model, (which is what this Chipmunk weighs) and the performance is great. It isa fantastic engine and worth consideration.

MinnFlyer

My Feedback: (4)

The ideal engine for this plane is an OS 91 Surpass!

ArcticCatRider

My Feedback: (6)

What do you mean cold turkey build?

Alex7403

There is a plywood tray for the bellcranck and a piece of balsa with a hole for the pushrod to exit.
I was thinking to make some sort of plywood tray for the servo because this balsa pushrod exit is not strong enough to carry a servo on it.
maybe two rails of hard wood between the ribs to hold a ply tray with screws in, but if there is a better easier solution I'll be glad to hear.

Thanks
Alex

Alex7403

cold turkey quit from cigarettes to keep my head busy with build.

bigal126

My Feedback: (18)

Congrats on quitting smoking. You'll be able to afford more planes now!

EscapeFlyer

My Feedback: (1)

WO HOOO!

ArcticCatRider

My Feedback: (6)

I gotcha....not a bad way to keep your mind occupied!

Alex, would someone living in Manhattan (Little Italy) have any reasonable access to a model airplane field? Or would have have to be in one of the outer burroughs?

DavidAgar

My Feedback: (108)

Minn, the Chippy does have cap strips. Dave

Alex7403

Well in manhattan there is no where to fly but you need a car anyway to transport it to the field, It can be done if avoiding traffic.
In brooklyn there is the best field i've ever seen - Floyed Bennett air field our piece of it is 300' x 900' concrete.

Alex7403

Doing the right wing.

Alex7403

Is there a better way to reinforce the landing gear mounting block?

if I put these harder wood blocks with epoxy between the spars and fiberglass it all - the doublers to the spars so the impact will be transfered to the spar instead of ripping out the plywood doublers.

what do you think?

scale only 4 me

My Feedback: (158)

+1,

my buddy had that set up in the plane,,, with smoke,,, it was awesome

spitfire60

My Feedback: (1)

Alex
The problem with landing gear is pulling the hard wood grooved blocks out of the rib with the doubler
I reinforced the hard wood blockes with triangle stock to keep them atached to the ribs -a problem others have had is splitting the two small blockes that the peg part of the landing gear wire in the wing.Make this part as strong as possible. in short you need more glue surface for the hard wood gear blockes. My chipmunk has flown for a long time no problems with blockes have bent the wires many times,but no problems with blockes.

Great fling plane mine has flaps just for fun not needed,people talk about engines ,mine has a os 46fx
with a 12X4 prop it flies very scale,doesnot go straight up for ever but does evry thing I have asked.
Have Fun With Great airplane.

Alex7403

You mean the whole long grooved block is being ripped out?
This is no good, I'll have to fiberglass it all from all directions then, also make copies of the ribs and make alternate landing gear setup on the fuselage.
The OS 91 4 stroke is beyond my budget I'm planning on a tower hobbies 75 and a new radio.

Thanks
Alex

dragonov3

My Feedback: (3)

I built one of these way back when. My friend just purchased a chipmonk kit off of e-bay. I am going to copy the kit and build two of these at the same time, one for him and one for me.
It is a wonderful airplane to fly. The 1st one I built had a OS .61 fsr on it, It was plenty of power. I built the plane back in 89. Have fun with it.
Dan

Live Wire

Alex
The main problem with the chippy landing gear is you have to land it not plant new Balsa. The only time I have lost a gear is in a hard landing , in the ruff area. Install them with a slight forward angle and have a good one
Larry K

scale only 4 me

My Feedback: (158)

understand the 91 is costly, just a great combo with that plane

spitfire60

My Feedback: (1)

Alex
you don't have to go crazy-just epoxy some hard 1/2 triangle stock in corner from ply doubler to all the

hardwood blockes-if it brakes after that you have bigger problems

this a fun plane that doesn't look like an extra or yak ,etc everyone at my club alway like a different

plane

[]TEX[]

Imagine all the money you'll save by quitting smoking.

One of the guys in our group did the same thing and wee figured it to be about $3500 per year.

I quit smoking years ago, after a while you wonder why you even started in the first place.

I also had this same Chipmunk when I was a kid. Built it with a 91 Surpass and that even seemed like not enough power.

Anyway, good luck!

Alex7403

I have some problemes,
I'm matching the wing halves for joining them, there is a mismatch between the spars and the lower sheets are touching each other.
The LE sheeting is just not at the same level 1/8" difference, the spars are touching each other its just on the table like this.

planebuilder66

My Feedback: (8)

Uh, I can't figure that one out myself either, I would start at measuring the ribs on the inboard side, make sure they're the same liength, if so, measure inward and make sure the distance to the sheeting edge is the same, if not shorten the longer side to match the other one, if all else fails, curse and flail your arms around like a 2 year old, hey, it works for me,.....sometimes. Trust me, I just resheeted my TF p-47, I managed to somehow warp the wing over 2 degrees in wash-out on one tip, it's only suppose to be 2.5 degrees. I ended up destroying most of the new 3/32" sheeting trying to fix the error. I feel for you, but you know what, it's a hobby, every challange is a test that only you can figure out and fix.

MinnFlyer

My Feedback: (4)

In the first pic, is it sitting on the wing supports?