Chip Shop

[john stones 1 - Moderator]

me too Ton

will cut my own parts

young ones today, always in a rush

[Tony F]

Guys may I ask how you do your cutting ? Is it something a noob can do or is specialist tools required ?

Tony

[Tony Bennett]

i use a scalpel and steel rule, just takes time thats all,

[Ton van Munsteren]

John, Thats the spirit and good to know we have all summer.

Tony, Only a sharp knife, small saw, copie of the part you need to cut, double-sided adhesive tape or an Iron to iron the print from paper to the wood.

Ton

[kevin b]

Can we discuss power systems yet, or should we wait until October ? My experience with electric flight (in fact any !) is limited, so I will need guidance in that department.

By the way Danny, I found reference to an Airsail Chipmunk build which came out at 7.5 lbs and apparently flew very well. So I would suggest that as a target weight, as they are both 1/6 scale.

kevinb.

[john stones 1 - Moderator]

you can discuss them for me Kevin, I need guidance

[Chris Bott - Moderator]

My usual method for power systems it to wait until I'm well on in the build, that way I have a much better idea of not only the likely all up weight, but also whether a model needs extra weight up front for C/G or not.

So I'd normally leave it for a long while yet.

I think 7.5lbs is a reasonable target, seeing as we don't have any more info at this point. I won't be surprised if it's lighter.

If we want scale Chippy flying, I think 100W per lb is probably too much. But using that rule of thumb, we're somewhere around 750Watts. So I recon something between 600 and 800W will be what we're after.

[Tony F]

Cheers for that Ton...How do I get a Plan scanned in to enable me to print out sections ? Or would it be prudent to get the originals copied and use the copies for the templates ?

OK I'm in and will be going electric also....and my scheme ? I'm quite intrigued by this scheme

Tony

[Martin Harris - Moderator]

Posted by kevin b on 26/03/2014 22:21:12:

Can we discuss power systems yet, or should we wait until October ? My experience with electric flight (in fact any !) is limited, so I will need guidance in that department.

By the way Danny, I found reference to an Airsail Chipmunk build which came out at 7.5 lbs and apparently flew very well. So I would suggest that as a target weight, as they are both 1/6 scale.

kevinb.

My Airsail Chippie with on-board glow, 2 pilots, oleo legs, an OS52 FS and a bit of extra detailing weighs around 8.5 lbs and has impeccable manners and more than scale performance - I habitually take off with half or less throttle to get a reasonably scale-ish take-off run - so I'm sure any equivalent power system will come in at a reasonable weight.

Edited By Martin Harris on 26/03/2014 23:48:43

[fly-navy]

Posted by kevin b on 26/03/2014 22:21:12:

Can we discuss power systems yet, or should we wait until October ? My experience with electric flight (in fact any !) is limited, so I will need guidance in that department.

By the way Danny, I found reference to an Airsail Chipmunk build which came out at 7.5 lbs and apparently flew very well. So I would suggest that as a target weight, as they are both 1/6 scale.

kevinb.

Certainly Kevin, Laser 80 for me all day long (Eh Danny!! )

[Glenn Stratton]

I've a Laser 80 lined up too, but after reading Martins post, 8.5lbs on a OS52FS (4stroke I presume? ), and Chris wouldn't be surprised if DB's isn't a bit lighter, I'm now wondering if an 80 will be a bit too much (I know I can use throttle control) and maybe not have to add any nose ballast! I do have a Saito 65 that I could use instead. What are other people's thoughts? I will be flying off grass also, are you flying off grass Martin?

[Colin Leighfield]

I think that the kind of power output we need is becoming clear. I mentioned before though that this could be the opportunity to have a first go with petrol. Does anyone have any thoughts on the Evolution 60 GX? Apart from the cheapness of running, I also have the impression that the low percentage of oil needed in the fuel gives a much cleaner exhaust, so that you don't get oil everywhere. Is that correct?

Also, Bob Cotsford is reporting good results with one in his Mustfire, but also comments on noise, so with one of these would it be possible to adequately silence it without having to accept a large external silencer? Otherwise perhaps I'll go electric, but I wondered if anyone has any thoughts on the petrol approach? I get the impression that the power characteristics of this 10cc motor could be right in the ball park.

[Olly P]

Hmm...foam wings and adapted for PSS....tempting.

Will see how much Shed time this year gives before committing to join in!

[john stones 1 - Moderator]

I use petrol Colin, I just get a bit of oil on model, cleans of easy

much cleaner than glow

silencing's is not that big a deal, there are lots on market available

some use the baffle inserts which are easily bought, you lose a bit of rpm but its a Chippy

and no doubt you'll find lots of useful advice on here

john

[kc]

The answer to Tony F's question is not to scan the whole plan but use an A4 printer/scanner/copier to photocopy the parts. Most items like formers, ribs etc on many plans will fit on an A4 sheet or maybe you can join 2 sheets together for the larger parts. ( make joining marks ) Just ensure the copier does not distort in one direction. The ones I tried -Epson & Kodak - made exact size copies. Sometimes its awkward reaching components in the middle of the plan but rmoving the copier lid and replacing with white paper and a heavy book to hold the plan down works OK.
Otherwise larger parts like fuselage sides can be traced onto tracing paper etc. Then either the photo copies or tracings are stuck to the wood with tiny bits of double sided tape and the parts cut right through the paper with scalpel or saw.

[Colin Leighfield]

John, thank you for that. If everything fits and there's no weight problem, this is probably what I will do.

KC, thanks also for your comments on printing, I've got a current model Epson and was concerned that distortion could have been an issue, so your experience is very helpful.

[Kevin Fairgrieve]

Way back in the mists of time....

Well in the 1990`s anyway, there was a Magazine which went by the name of Radio Control Scale Aircraft or RCSI.

I bought it on a regular basis, and even saved some of the plans and information.

Now it just so happens that the Dec/Jan 1997 edition contained a plan and scale detail for a Chipmunk.

I now have my chosen colour scheme. I just need to get lots more pictures of it. So if any one has any of the Army Air Corp one then please let me know.

If any one would like the higher resolution PDF files, please PM me with your email address.

Kev

[Tony F]

kc much appreciated mate that helps a lot so thank you !
Yes please Kev sending pm

Tony

[Kevin Fairgrieve]

Tony.

email on its way.

Kev

[Danny Fenton]

I would be grateful for a copy of the higher res doc if possible i will drop you a PM with my email Kev

Is this the scheme you fancy?

Cheers

Danny

[Graeme Poke]

Further to Kevin's post regarding RCSI, the March/April1999 issue no.11 of RCSI, the editor, Simon Delaney, completes the build of the Dennis Bryant Chipmunk started by someone else.He used a O.S.70 Surpass four stroke and it had more than enough power. He was very happy with the result.

I have been building this model for about 18 months. Progress is slow. Life keeps getting in the way.

By the way, I am the builder that suggested I may use a Saito 115. I thought better of it!

Cheers Graeme

[Danny Fenton]

Hi Graeme good to hear your views, and nice to know the 70 is enough. Looking at the cut parts and the construction methods on the plan this will build into a very light model. So I am not really surprised by the modest power required. I have an 86" Chipmunk and though an artf it is very light, and the motor I use is not much more than a 40 size equivalent, the Turnigy 4260 500kv. I have to start a loop with a shallow dive, but to me that is how it should be.

Was there more information in RCSI about Simons build? I would be interested in how you/he tackled the rudder attachment sequence, and also the join between the fabric and alloy sections of the wing?

For those of you with the plan, you may want to study these two areas. Also have a think of a lightweight method for making the tailwheel steerable. For competition it is not really necessary, but in my opinion I would always make it steerable, not all flying sites let you wander out to the end of the runway with your tx, and taxiing is the order of the day

Cheers

Danny

[Chris Bott - Moderator]

Danny and I had a good look over the plan together, something else we decided to mention was that for now, those with laser cut parts are advised NOT to remove any parts from the sheets.

For example, we had a good look at the tailplane construction. This is symmetrical but tapered, so each side, every rib is different. It is all built on a tapering rear spar, and the ribs are "fatter" further forward than the spar.

To get a nice true tailplane, then, will require some jigging. The easiest way to provide a jig may well be to leave the ribs in the stock, and cut a common line, parallel and below the rib centre line.

We haven't checked that there's actually enough "meat" to do this yet, but leaving everything in the stock wood seems good advice at this point. This jigging may work for other parts too.

[kc]

Colin L & Tony F and anyone cutting parts from plans. Check carefully that any printer/scanner does not distort and also prints same size! A simple test of a measured scale ( vertical and horizontal) and also of a circle could ensure you dont waste lots of time and material making over or undersize components. Also keeping the plan flat by weighting down with a heavy catalogue or something is important for accuracy.
My Kodak ESP3 and very old Epson 680 do not distort. Commercial large size copiers seem very liable to distort in one direction.
Of course water based adhesive should not be used to attach paper to wood because of shrinkage.

[kc]

Kevin has confused the names of 2 different magazines -RC Scale Aircraft Quarterly ( later marked "International" when Graham Ashby was Assistant Editor)was a Nexus etc magazine same as RCME etc, while RC Scale International edited by Simon Delaney was a Traplet magazine. So they came from rival sources!
I declined to put the RCSQ 3 view on this thread because it is copyright of a rival publisher to the one supplying the plans and parts for the Chipmunk we are discussing here!
Perhaps David Ashby will be indulgent on this occasion for the sake of aeromodelling!