Topic: Chipmunk

Gents,

I am about to start a refurb ona 102" Chipmunk.

Its going to have a Zenoah 62 up front and will have a tow release fitted for maggot dangling.

Its not going to need a huge amount of work   . (probably the wrong thing to say), however.

Is there any interest in a refurb thread.

Charlie C

Rude not to

Keith

wahoooooooooo, yes please.......

Definitely. I learn new stuff every time someone else shows their efforts.

Watching with interest......

s, is it going to be black, red or yellow... 

Yes please zur,another iconic british aircraft in Charlies hands,chuck it over here when you have no room for it with all these builds you have going
Albert

Chippie build thread ??
Your damn right !

s, is it going to be black, red or yellow... 

Gonna stay in Red/White and whatever sort of grey the other colour is.

Charlie C

YAY, yes please Mr C, but you knew that already   

YAY, yes please Mr C, but you knew that already:

Will do some as it is now piccies later on.

 

Charlie C

Yes please zur,another iconic british aircraft in Charlies hands,chuck it over here when you have no room for it with all these builds you have going
Albert

Not much chance of that. As well as looking nice, this one has a job to do.

Hauling maggots 

Charlie C

Lets have some pics then!! C'mon

Lets have some pics then!! C'mon

At Once Sir Ian  

OK here goes.

The fuselage. Its a bit tatty with a few minor splits and dings but in the main sound enough.



The front end needs some work though. A Z62 radial mount fits perfectly though what engine was actually fitted in a previous life I have no idea.



My Z62 fits perfectly and the prop driver lines up with the cowl nicely



The exhaust is a bit of a "Large" affair though. Dont think that will be there this time tomorrow.



The tailplane is removable which is a bonus, the the push rod is in my opinion only fit for stirring paint



And staying with the tailplane, the elevator horn is a floppy plastic one. Not happy with that and I suspect its only epoxied on  , though how I go about remedying that I don't know at the moment.



The wing is sound enough, though the standard servos fitted are coming out. sadly they are covered over in solertex, but I'm sure that it wont be a problem.





Which leaves the undercarriage. I am sure that these are an afterthought. They will work oK but I have never seen a mounting such as this. Still, if it works.



So, there it is.

I don't want to spend the next year on it. I intend to sort out any issues and dings and things. Rebuild or strengthen the engine mounting and I am tempted to glass it as well. Its had a bit of a hard life but seems to be sound, just needs some work.
The cowl needs chopping and shutting around the Z62 and the canopy needs new glazing, which I can do with flat sheets by the looks of it. The tailplane needs sorting then we will be ready for a quick respray to tidy it all up, hopefully.

We think its from the Mike Smart stable and Flyerpete has given me the Cof G at 5.35 inches from the leading edge. If anyone knows any different, please let me know. Control throw would be handy as well.

Right then, off to my new playroom we go.

Charlie C

Charlie that looks nice and I am sure it will scrub up well in your capable hands
Bring it on baby
Albert

Charlie I haven't forgotten that you asked for photos of the Chipmunks that were at the DH centenary but I've not been able to get to my photos as my PC is still faulty!  

Yup, the vendor has got the worst customer service (and I use that word very loosely) possible - avoid them like the plague (Overclockers.co.uk). I'll be contacting Trading Standards on Monday.

Anyhow, I'll let you know if/when I can get the photos.

Richard

Thanks Richard.

Don't worry on my part.

I have a few errrr Ahem weeks yet 

Charlie C

Ah! poor AN2, gets put in the corner again

Bonzey

Ah! poor AN2, gets put in the corner again

Bonzey

Ahhhh,

Thats where your wrong Mr Bones  

The AN2 has been de-dusted and broken bits are being put back on.    

Charlie C

Thinking of getting a large Chipmunk, like the Apache Aviation one. Might do it after my dad's version at Liverpool Airport.
Just had a new scheme, from red to black. Looks different - and like the motifs that would make it unique...

I have ripped off most of the oil soaked/rotten wood off the front end. (Piccies to follow)

The original engine mounting holes seem to be very high on the fuselage. I normally measure up across in the centre of the firewall and use that as a reference thrust line.

Anyone know where the engine centre line should be per chance 

Thanks

Charlie C

As promised, picture of T front end, or rather whats left of it.

The bottom and sides were out of lightply. One side and the bottom were oil soaked and errrrr, flimsy, tother side was not to bad, however, bearing in mind I'm going to bolt a Z62 into it, and do some towing, I have decided to replace the lightply with proper stuff, i.e. Birchply.

I have left the top section on so as not to lose any datum points, once the sides and bottom are on, it will get the same treatment.

Got a bit of a hole at the moment though.





From inside the fuselage looking forwards.




I have just been measuring up. I'm a numpty 

If I put the engine at the firewall centre line, the prop driver will come out of the air intakes at the front of the cowl and not the proper hole.

Ah well, onwards

Charlie C

Ahhhh,

Thats where your wrong Mr Bones  

The AN2 has been de-dusted and broken bits are being put back on.    

Charlie C

''Broken''  Charlie, you havn't finnished it yet, how can it be broken

Bonzey

Done a bit more these last few days.

The front end has been rebuilt and is nice and solid and Z62 proof.









Now that its all nice and solid, I knocked the blocks off the front and bolted the Z62 on.

 

Ahhhhhem.

Now the embarrassing bit.

Damn things 20mm to long for the cowling.

Damn and flip, I measured it all wrong.

I now have 3 options.

1. Cut the front off and recess by 20mm. Not as drastic as it sounds, and being as the 62 is going in place of the designed, (I believe)28 may help with balancing issues.
2. Extend the cowling mountings by 20mm. Not difficult to do, but may look a bit errrr Odd.
3. Take 20mm off the prop driver. Need to look at that one.#

 

Its been a busy day. That's my excuse anyway.

Charlie C

Ah, the magical moving measurements- I get those too.

sorry to hear of your problem, but I'm also glad I'm not the only person who suffers from them.

Charlie,
 before you take the saw to what you have built there, can you not change the radial mount or the prop driver? various sizes are available. just a thought.

Bonzey

Charlie,
 before you take the saw to what you have built there, can you not change the radial mount or the prop driver? various sizes are available. just a thought.

Bonzey

Thanks Ken,

I am going to do some measuring up tonight and see if its possible.

 

Charlie C

Thanks Ken,

I am going to do some measuring up tonight and see if its possible.

 

Charlie C

standard options on here, but i am sure you would machine one up for yerself...

http://www.glensmodels.com/2005.htm

You could remove the top hat mount and fit a flat plate, with a hole in the firewall for the rear end of the crank

Ian.

You could remove the top hat mount and fit a flat plate, with a hole in the firewall for the rear end of the crank

Ian.

good idea.... 

You could remove the top hat mount and fit a flat plate, with a hole in the firewall for the rear end of the crank

Ian.

Oooohhhhhh,

Never thought of that one.

Gonna get me ruler out in a mo.

Thanks Ian 

Charlie C

Had a bit of time in the workshop again today. Unusual for me on a Saturday.

It doesn't look so pristine in there now.



Anyway, after lots of measuring, hmmmmmming and hhhhaaaaaaaing and generally pontificating, I couldn't find any material in my stockpile for either knocking up a new, shorter prop driver, or alloy/steel sheet to make a new engine mounting.

I have however, got loads of wood.

So, in case you cant guess what comes next,



10 minutes with a jig saw, and sanding block and we have an engine box that is 20mm shorter. Luckily I managed to cut/sand it more or less square.

I have decided to make a new engine mounting former as well.

It has only taken a few hours, and I have actually fitted the engine/former/cowl and it all fits. Just going to glue the engine former on now.

Charlie C

Just fitting a square firewall into that hole?? Will that give you enough firewall at the top end for the engine, or does that pic give a false impression and its all hunky dory, since the pic makes it look centred and not biased towards the top end of the fuselage.

Ian.

Just fitting a square firewall into that hole?? Will that give you enough firewall at the top end for the engine, or does that pic give a false impression and its all hunky dory, since the pic makes it look centred and not biased towards the top end of the fuselage.

Ian.

Errr no Ian,

Well I think no.

I'm just going to upload a coupe of piccies and all will become clearer 

CC

Charlie, at long last I have those photos for you. Hope they are useful. I have hi-res versions of each I can send you if you would like them.

Richard

Hi Richard,

They are great, just what I was looking for  

You have just found me an aircraft to replicate. it wont be a work of art like a certain Tiggie, but it will be still good enough for the odd show or two next year  .

Right then Sir Ian, hopefully the following pictures will explain all. If it ain't enough pleeeease say so before I start bolting the Z on tomorrow.







The inside frame is Cyparis and the new bulkhead is 6mm birch ply.

Hope that's gonna be enough. T'wold be embarrassing is the Z popped off with a glider on the back.

Having had the debate on Scale soaring about tow release positions, and, having seen Sir Ian's Robin towing with the release at the back of the canopy, I was just wondering about putting the tow release behind the canopy.

What do we think???

Charlie C

Glad I could help

Some more here http://www.airliners.net/search/photo.search?regsearch=WD325

Richard

Looking good Charlie,nice subject to model it on
Batteries came in useful then
Albert

I'd definately fit the release there matey. One thing though, on my Robin the towline exited the fuselage at that point, the release was at a much stronger point near the mainspar. The line ran through a guide from the top decking to the release point. This guide was simply snake outer, well secured at both ends. I did this purely because I didn't want to add the weight of the servo, release and some beefing up that far back. In use it worked perfectly however, not a single problem. Your Chippy could use a very similar system if you are worried about weight and strength in that area. It need'nt be a straight run for the snake either, a sweeping curve is fine as long as it is in the general direction. Test it yourself, pull a length of towline out, pull it tight, whilst its tight, pull the line to one side, its very easy to pull it a way off line. I,ve seen a few tugs that have added pounds to a structure because they've beefed a part of it up to get the tow release at the outside skin, only to have to compensate at the noisy end. Sadly mine was written off in a mid air by its new owner after I'd sold it or I could show a pic of my set up.
Ian.

Hi Ian,

Thanks for all that. I remember having agander at it at Osbournby before you sold it. I think I can remember the set up.

There is so much room in the fuselage, I am reticent to put the release servo up t back as it were, so the remote release work for me

I am slight concermed about stability in pich wen towing with the release at the back of the canopy, but it can't be to bad  would have thought.

Do the the engine mounting piccies make it clearer now ??

Charlie C