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Indoor Scale Candidate

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Colin Leighfield16/01/2017 10:21:35
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5952 forum posts
2492 photos

That's really dropped me in it. I'm working on the drawings and haven't worked out the power train yet! It's got to be a much simpler build than both of yours and I haven't got a clue whether I can get the weight right. I had a quick look at the numbers and it needs to be about the same weight as Danny's by the looks of it.

We're off to Spain for three weeks on Saturday, if I haven't finished the plan before I go I will do it over there. It will actually be a simple build and should go together quickly. Whether it's going to fly or not will be a different question.

Danny Fenton16/01/2017 12:04:16
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9106 forum posts
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Colin if you want me to remove your name from the piece let me know asap, the copy goes to the 'Ed today I really didn't want to put you on the spot my friend

Colin Leighfield16/01/2017 12:19:10
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5952 forum posts
2492 photos

Danny, not at all. It's a challenge and I'll have a go.

Paul H16/01/2017 18:55:53
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35 forum posts
47 photos

dsc03875.jpgdsc03872.jpgHi Martin

Your build looks great and has me seriously worried, rib tapes and stitching! I am building a Sopwith Triplane from the Aerographics kit for the Indoor RC Scale Nationals having never tried anything of this nature before. The airframe is all but complete and I have started covering, doing 6 wing panels today. Like you I have bought my Electronics for motor, rudder and elevator from Micron, good advice and service. Target weight is 150gms

I am sceptical that I have done the right thing and may quickly build a simple high wing model which is more likely to fly well. Good luck with your build.

Danny Fenton16/01/2017 19:26:21
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9106 forum posts
3945 photos

Terrific Paul, another one taking part! And that model looks superb, that's the 24" one isn't it? Have you checked the wing loading? If you can add ailerons then go for it I wish I had.....

"The maximum wing loading of the complete model in flying condition including all power packs is 15 gm/sq dm"

Sorry Martyn trampling all over your thread embarrassed

Cheers

Danny

 

Edited By Danny Fenton on 16/01/2017 19:33:34

Danny Fenton16/01/2017 19:43:35
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9106 forum posts
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Just spotted one on Mike web page, near the bottom of the page, builder John Ernst, 50gms

Cheers

Danny

 

Edited By Danny Fenton on 16/01/2017 19:44:11

Paul H16/01/2017 19:46:31
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35 forum posts
47 photos

Too late for ailerons, not least because I think they would drive me mad. Planning the RC installation and all the rigging points not to mention the instrument panel, Clerget engine and other detail has been a trial. I think I have actually built at least 2 Tripehounds given the number of times I have made a trial assembly and then built a final version sometimes at the 3rd attempt. Still to work out the wing loading, probably too scared to. Thanks for your encouragement though Danny.

Martyn K17/01/2017 09:25:11
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4916 forum posts
3580 photos

Hi Paul

That looks lovely - I think it will fly well and I am looking forward to seeing it.

Don't worry about my comment about stitching and rib tapes. I was just trying and failing to wind Danny up..

.. or was I. He he

Danny Fenton17/01/2017 09:55:06
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9106 forum posts
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I was in shock Martyn....... I was wondering whether I had time to recover my Cub

john stones 117/01/2017 11:10:07
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10592 forum posts
1480 photos

My mind boggles at what you're building, Triplane's fantastic Paul yes picture of the Cub Danny, or is it a secret for now wink

John

Danny Fenton17/01/2017 11:12:00
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9106 forum posts
3945 photos

Hi John, the Cub has been in two editions of RCM&E so hardly a secret

Cheers

Danny

john stones 117/01/2017 11:39:09
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10592 forum posts
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Ooops that's me caught out then, i don't always get the mag embarrassed

Superb Danny, and i can't see any trimming on the waggly bits yes

John

Danny Fenton17/01/2017 11:49:32
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9106 forum posts
3945 photos

Tsk tsk John

I am quite pleased with the model, my first foray into indoor R/C design. It might be a free plan in a future RCM&E if my scratchings pass muster. I am however struggling with the C of G, these smaller models require a slightly further forward C of G than normal (20 - 25%) and it has cost me dearly..... 10g of nose weight crying 2

Interestingly the model turns quite well considering almost zero dihedral....

Cheers

Danny

Martyn K18/01/2017 14:39:05
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4916 forum posts
3580 photos

Completed the tailplane:

dscn3372.jpg

Then scrapped it because it was too heavy (just over 3 grams)

Version 2 underway..

tailplane1.jpg

This one has the outline laminated from 1/32 soft balsa (3 laminations) and then are a mix of thin and thick 1/32 balsa ribs. (Thick ones where I need a stronger glue joint)

Need to add the trim tabs, sand to shape. I am then going to cover and water-shrink the bottom of the tailplane and a mist of thinned dope. Pin the tailplane back down again with the tissue side downwards then add the short riblets, gluing to the LE and tissue then add the upper covering. Hopefully that will give me the appearance of scale rib spacing without any excess weight.. It may also means scrapping it and starting again.. If it works, I'll separate the elevator using a single sided razor blade which is thinner than my Swann scalpel blade. Hinge using cotton like Danny did on his Cub

Just to add to the irritation, the hinge line for the elevator isn't quite perfectly straight

More to come

Martyn

Danny Fenton18/01/2017 14:52:56
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9106 forum posts
3945 photos

Hi Martyn, good idea. The same thought sprung to mind as to attaching the riblets to the leading edge and tissue. The profile is no doubt flat on the bottom. Will be interesting to see if it works You could just leave the riblets off and give the rest of us a chance

You may want to pre shrink your tissue, and use banana oil to stop excessive shrinking

Cheers

Danny

Martyn K18/01/2017 15:17:01
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4916 forum posts
3580 photos

The tailplane with the core used a NACA 0006 section. The new one will be mainly flat... The challenge will be not to let the glue seep through the tissue. I detect a Pritt Stick on the horizon..

Tissue on order - hopefully today. Got some Silver lightweight Esaki coming which will hopefully only need a smattering of paint to give it a nice sheen.

Martyn

Danny Fenton18/01/2017 15:29:31
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9106 forum posts
3945 photos

Yep great choice on the silver esaki You might be okay to just add the riblets to the leading edge, and not actually glue to the tissue at all..... Let the dopebananaoil stick them

Martyn K18/01/2017 15:33:07
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4916 forum posts
3580 photos

Don't trust myself. It will go pear-shaped when the tissue goes down and then its too late. They will be stuck to the tissue - just enough to hold them.

Martyn K19/01/2017 09:54:58
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4916 forum posts
3580 photos

The new tailplane weighs 1.3 grams. 2 grams lighter than the version with the wooden core. Still a bit on the heavy side, the tail moment is quite long and the nose is quite short I don't want to add nose weight unless I have no choice.

I started sanding it down last night. Apart from being a bit porky I am quite pleased with it.

So, I bit the proverbial bullet and made a start on the wing last night. Wing construction uses 'hollow' wing ribs, basically a cap strip with no supporting wing rib - top and bottom.

One challenge is to get the LE located so it wont move while the wing is being assembled. The LE is diamond orientated so I made a jig from 2 strips of triangle stock - like this

wing5.jpg

The LE (and TE) is slightly curved so a sliver of clink film added into the Vee..

wing1.jpg

You can just see the LE in there somewhere

wing2.jpg

another view

wing3.jpg

TE and lower cap strips (1/32 x 1/16 wide) added

wing4.jpg

and then the lower spars added.

Left to dry overnight. I added one top cap rib this morning - 1/16 x 1/32 wide (precut to the upper curvature) this morning and left it to dry. This bit is going to take a while.. and I have 3 more wings to do..

More to come but now slowly

Martyn

Martyn K24/01/2017 09:50:16
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4916 forum posts
3580 photos

Still plodding on with this. I cant pretend that the dialogue is riveting (sorry Danny). Its basically a case of add a few ribs, jig them in place using pins, let dry and then add a few more. However, my productivity has improved. It took 5 elapsed days to assemble the first wing, only 2.5 days to do the second..

A couple of photos - both upper wings are now just about complete.

wing6.jpg

Right Upper wing with riblets fitted.

wing7.jpg

Laminated wing tip for the Left upper wing. Riblets trimmed/sliced back to the spar.

wing8.jpg

its handy to be able to weigh the ribs down when the glue dries. the Swann Morton no 4 scalpel also gives a good sense of scale. I normally use a no 3 handle and razor blade on this sized model

 

Amazingly, I have only broken one wing rib so far.

The right upper laminated wingtip was fitted this morning.

I now need to think about how I am going to actually fix the upper wing halves s onto the fuselage top and then worry incessantly on how I am going to do the ailerons and the swivel panels for the wing fold mechanism.

Its now getting tricky.. 3 weeks into the project and 6 weeks left to get it completed. This is going to be tight. A Kwik Fli is an absolute doddle compare with this..

More to come.

Martyn

Edited By Martyn K on 24/01/2017 09:50:42

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