Sharkface EP

[Major]

Welcome All!

 

Just yesterday I have started to build Sharkface. I need to say - my whole experience with traditional building bases on 3 models from Guillows - JU-87 Stuka, P-51D Mustang (my first covered model) and Cessna Bird Dog. Between them was another Stuka (eaten by cat - half finished) and West Wings Spitfire - unfortunately that one gone to bin as at that time just couldn't read the plan properly, and all my tools contained nail polishing block and not really sharp hobby knife.

 

I hope this time it's gonna be better. Have checked already all parts I cut and everything seems to match others. Also my toolbox got a bit fatter.

 

In next few hours I will post some pics as I take them regulary. If anybody has any advice about building just please post here.

 

All the best.

Tom.

Edited By Major on 31/01/2012 03:31:09

[Big Bandit]

Hi Tom,

 

There's a few idea's Here. It would be interesting to see how you get on with your build, and it goes together really quickly. Thinking about it there's no reason why a brushless set up won't work well, but I would go for a higher Kv motor and keep the prop size down if I built another for electric.

 

Cheers,

 

Chris.

[Major]

Hi Chris.

 

I have seen Your thread more times than You can imagine - and it's very helpfull indeed.

Well, I don't expect it will go fast as after (or maybe even before ) hobby I've got two children - 3 years and 14 monts - so You know, it might be pretty hard to find as much time as I would like to have, but will do my best of course..

 

I am not an expert in motors, but I have seen this - http://www.airtekhobbies.com/1450b.html.

 

Is it gonna be ok with 9x5 prop?

 

Another question is about hinges - where did You take nylon from??

 

And please don't get me wrong - I don't want to be like a parasite, but for sure will ask some more questions as work moves forward.

 

Regards.

Tom

 

 

[Big Bandit]

Hi Tom,

 

No problem ask away, The nylon is from some covering I brought for the Super 60, but any light weight fabric will do just as well.

 

If I build an electric Sharky I would use either a pole and stator motor of about 2300 Kv on a 2s lipo and a 6 x 3 or 6 x 4 prop or a bell type motor of similar Kv. That should replicate the characteristics of the cox motors fairly well.

 

I use a pole and stator motor in the quiver which is a slow flying vintage thing, but I've kept the high Kv and smaller prop to try and match the characteristics of a small diesel, and it works well. Those motors came from Robotbirds at about £7.50 each £1.50 for the mounts. I think BRC do a similar motor at the same price.

 

Cheers,

 

Chris.

[Big Bandit]

Tom,

 

 

This would be my choice of motor Here .

 

Cheers,

 

Chris.

[Major]

Thanks for advice Chris. On Friday I'm gonna order this motor.

 

Work moves forward, but slooowly. Currently I have one wing nearly finished (sanding was not so nice). And as I thought, model won't be perfectly straight;(, but I build first time something like that. There is a difference of about 1-1.5mm across leading edge.

 

To copy parts from plan to wood I use some old tissue from Guillow kit. First I copy the plan, after stick piece of paper to wood with dope, then cut to shape and sand. A bit time-eating method, but as far as I can see - works quite ok.

 

Here You can see, that it even matches to the plan.

 

After cutting all ribs from 1/16 (12 pieces) and 3/32 (3 pieces), spars and edges, my wing looked like that

 

And here is nearly finished left wing. I never liked sanding and not gonna like it. I just hope, that very small bumps on leading edge will not affect flight;(.

 

Today I'm going to finish second wing (gluing and sanding - it's still pinned to my workbench) and cut off fuse and tail, so more to follow later.

 

And now questions:

Could I use a tissue from a Guillow kit to cover this plane?

 

How to stcik tissue to the plane? Till now I used hi grade dope on my Guillow's kits, but maybe balsa cement will be better?

 

Could I use celluloid to make hinges instead of nylon?

 

And by the way - I would not say that this hobby is very healthly. I started to smoke about twice - three times more than usual... But my cancer loves it.

 

Cheers.

Tom

Edited By Major on 01/02/2012 14:35:15

Edited By Major on 01/02/2012 14:36:39

[Big Bandit]

Hi Tom,

 

From the look of your photographs your doing well, just take your time and enjoy what your doing. To be honest I use dope to stick the tissue to the frame. Just give the frame a coat of dope and leave to dry. Then place a piece of tissue cut about 1/2 inch to 1 inch larger than the frame your covering and using thinners just soak the tissue while pulling it tight and even, along the length of the frame. The thinners will soften the dope and make it sticky. allow that to dry. Then thin the dope 50% dope and 50% thinners. Spray the tissue with water and it will shrink and pull very tight. when this is dry give the tissue a coat of the thinned dope to tighten it further.

 

If you have a local model shop A ask for some JP light weight and heavy weight tissue. Use the light weight on the fuselage tailplane , fin and rudder, and heavy weight on the wings. If you have problems getting any PM me an address and I'll send some by post.

 

Just a word of warning if you use shrinking dope on the tailplane fin and rudder the thin balsa will warp so if you can get some shrinking dope and a small tin of none shrinking dope. Always use the none shrinking dope where you are covering thin sheet surfaces.

 

As for the hinges, I've used any thin material in the past for these, one of my favorites is finger bandage cut into thin strips and stuck on with balsa cement. When I was young I had to improvise and use what I could find in my parents house for my models , I've even been known to cut a strip off of the bottom of the net curtains for hinges, my mum always blamed the curtains for shrinking in the wash .

 

Cheers,

 

Chris.

[Major]

Chris, thanks very much for advices again!

 

Of course I do enjoy what I'm doing, even if my woman moans about dust etc.

 

When I covered my planes, just coated the frame and then, while dope was still wet, placed tissue on it and pulled a bit. After it dried I applied another coat of dope to whole tissue, and that was pretty much everything. I didn't use water first, but will try.

 

I don't know where I could buy any tissue around Preston. Have checked Hobby Craft and Speedy Models, but found just nothing. So I will PM You my address, and You could send me some please. Of course I am willing to cover any costs like P&P and the material itself.

 

I have spotted when covered one of the wings of my Bird Dog, that tissue can do strange things with construction. One of them just looked like banana, but luckily I have dealt with it.

 

So I guess, celluloid will do just fine as material for hinges. And I wouldn't like to be Your mother. I remember, when I was about 12-13, once have been playing with fireworks. And I have blew up the toilet, but it's another story

 

Ok, will just PM my details to You, and then get back to my plane.

 

 

Thank You very much for Your help. I am grateful for that!

 

Cheers,

Tom

[GeeW]

On thin sheet balsa tailplanes, fins etc. sewn hinges work really well and are very easy to do, slop free with just about zero friction.

If you look at the models section in www.singlechannel.co.uk there are some examples to view.

 

I am just about to start a Sharkface myself, e-powered and will be flown 'compound' mode on single channel.

 

Gordon

[Major]

Thanks for advice GeeW. I considered using sewn hinges, but will stay with celluloid. It looks more "damage resistant" to me.

I moved forward again with my Sharky. After doing first wing, glued another one. Here is one photo for comparision

 

After few minutes and many cigarretes, my job's effect looks like that:

So it's nearly done. Just need to do some more sanding to make LE & TE quite level, add some gussets and cover!! So maybe plane will be completed before Sunday night. I did check how covering fits to the wing - used some old tissue from Guillow's kit. And suprissingly it does match and fits nicely.

 

Of course something had to go wrong. Wing dihedral is a bit lower than it should. Will have to leave it as it is...

 

[Steve Hargreaves - Moderator]

Watching with interest Major....Chris was kind enough to send me the Sharky plan as I fancied building one for an old DC Wasp motor I have (My first motor...bought when I was 11).

 

I ran up the motor recently & it won't keep going for more than a minute or so...I think its just worn out. So this gives me a dilemma as to whether to build a Sharky or not.....my Wasp has nostalgic value & I'd love to see it flying again but if I was to replace it with another motor....well that would just be another motor not MY motor from 35 years ago......so what to do....??,,,Maybe an electric version might be fun if a bit heretical....

 

As you are in Preston then I would suggest Blackburn Models. This is my local shop as I live just north of Chorley......he sells dope & tissue & things.....

[Major]

I have received my plan from one gentleman from previous job. It is an original one from '65. I would never say that I'm gonna use it, as basically I wanted to just fly... About few weeks ago things changed.

 

Of course it is a heresy to put electric motor into Sharky, but from my point - very economical indeed. If I get normal job, nothing will prevent me from building another one with proper engine. Good training, good fun!!

So what I would say - You just build Yours!! It would give a group of 4 Sharks - Big Bandit, GeeW, me and You.

Thanks for info about the shop. Will check it as soon as will find the way to get to Blackburn!!

Just came back from local shop. Gave a nice smile to shopkeeper, and found out, that weight of my wings by now is 20,5gm

[Big Bandit]

Hi Tom,

 

Tissue will be in the post tomorrow, I've just covered the bottom of the Super 60 wings today so I'll lob in some nylon offcuts for your hinges, your Sharky is looking good so far.

 

Steve, if you want some bits for your DC Wabby I've got some hanging around doing nothing give us a shout if you want any bits. I've also got loads of Cox's if one of those would be better.

 

I've just got a gig in March to do an introduction to aero modeling in Sheffield for a group of upto a dozen. Tomorrow is down to the BMFA for some kits, and shop around for some plaster board for small building boards. I recon some indoor stuff is the order of the day, but there is a park next door to the venue for some aero's with the T28 and F4U. Looking forward to this one.

 

Cheers,

 

Chris.

[Major]

Thanks for that Chris!!!

 

Work moves slowly... Right now I did a fuselage.

 

To copy plan onto the wood, first I drawn fus's shape onto the tissue and stick to wood with dope. Then cut to the lines, draw another part from the first one and of course remove tissue from the wood. I love it as much as sanding... And I have seen confirmation of BB's words - doped tissue wrapps wood.

 

Fuse sides are cut from 1/16 sheet. To add some strenght, I cut two pieces from 3/32 and placed on the front of fuselage.

 

 

On this photo You can see all parts after sanding together (like Big Bandit did), just before gluing.

 

 

Everything is glued already. Now I'm cutting formers. Next thing I've learnt - If you think You're gonna be ok with amount of wood, just buy some more.

From 3 days I visited Transport Models three times to buy some more balsa, and of course right now ran off again...

 

More info about progress a bit later.

Cheers

Tom

[Major]

Could anybody tell me, what ESC should I buy to suit motor from BB's link?

 

I have found on ebay THIS . Will it be ok??

 

And what battery will match? I am in doubt right now, as fuselage is nearly finished, but I just don't know how much space inside I will need and how to place everything to keep CoF in correct place. I am a bit supprised that battery like this is twice heavier than my wings!!

[Big Bandit]

Hi Tom,

 

A 20 Amp ESC should do the trick, any larger is a bonus.

 

I've had a look at the battery you posted the link to, and it's too low on capacity, your only going to have 12.5 amps at 25C to use. may be it would be better to go for a 2S pack of a higher capacity, say 1000 mA/h so you can pull 25 Amps and a 2 cell pack will be lighter than a 3 cell pack of the same capacity. Some thing like this. Here

 

What you also need to avoid is running the lipo at it's maximum rating, ie 25C far better to run it at 15C , it'll last longer and you'll have longer flights, the same with the ESC so a 1000mA/h lipo running at 15C (15 Amps) 20 Amp ESC, 1800 Kv motor on a 6 x 4 prop would be my starting point for an electric Sharky.

 

As you intend using a high Kv motor you should be able to spin a 6 x 4 prop at about 13,000 rpm on a 2S lipo which is about as much as you would get from a Cox 049

 

Hope this helps, Cheers,

 

Chris.

Edited By Big Bandit on 03/02/2012 09:40:17

[Steve Hargreaves - Moderator]

All good advise from Chris there Major.....we want to keep the original character of the model so a small prop turning at high speed is what we want. I'm guessing that Sharky will be somewhat under 1lb in weight so anything around 100watts will see it disappear at a great rate of knots.

 

I might be tempted by a slightly higher kv motor however.......maybe around the 2000 to 2200 mark. I have a 1650kv motor which develops 95watts on a 9x4.7 slo fly prop on 2S so to get a 6x4 to work at that level you'll need to spin it a bit quicker!!!!

 

Alternatively keep that motor & use an 850mAh 3S battery.....the smaller battery will reduce the weight & the higher voltage will get the revs up & reduce the current for the same power which will help the duration.....

 

If you can bear with me until a bit later I will try a 6x4 on 3S on my 1650kv motor & see what happens......

 

@Major....Blackburn is easy to find & if you're not sure kick a guy on the shins....if half the population starts limping.....you're in Blackburn!!! Another chap on the forum has a Sharky too....with a Cox 049 in it....Lee Damms was responsible for stoking my & Chris's interest I think!!!

 

@ Chris...thanks for the offer...I might take you up on that....I think its a new piston & liner it needs...as it gets hot the compression just bleeds away I think. I worry that it might end up like Triggers broom....3 new heads & 4 new handles but its the same broom...right!! I also have an ancient Cox which runs but not very well.....that has a crankcase leak though....I know I can see the bubbles between the crankcase & the tank!!!

[Big Bandit]

Hi Steve,

 

The Cox is the best bet for the Sharky, because it has it's own tank and bolts direct to the front former . I'm still a bit miffed at the guy who turns up the diesel heads, some light ally or brass shim might work, without any it just bleeds compression past the contra piston.

 

I make my own gaskets and for the coxes it's just stamp out a hole in some thin brown paper to fit over the tank spigot, then bolt the tank to the motor, When it's all tightened up I cut the excess paper off with a scalpel.

 

Tom what Steve has recommended sounds good to me, the Sharky was designed for small motors that scream away so the faster you can get the prop spinning the better. when the Super 60's finished I'll do a lecy Sharky just for fun and see what works.

 

I'm not sure how far Blackburn is from Preston, but having looked at the web site for the shop that you use, it would be worth traveling a short distance to get some good stuff from Blackburn.

 

Cheers,

 

Chris.

[Steve Hargreaves - Moderator]

Well what a great little set up for a Sharky.......

 

I tried this motor with an APC 5.4x4.5 prop powered by a 1000mAh 3S battery.....I got just bang on 100watts at 10.6 volts (9A) & a draft from the prop very akin to a Cox 049...

 

Add a 12A ESC (small & light) & you have a great fun model....1000mAh battery here or possibly a 800mAh to reduce the weight a bit although probably not worth it for the 14g you'd save....

 

Theoretical duration would be around 6 minutes flat out....probably 7-8 in the real world & I think you'd probably need a lie down after that.....

 

Most excellent as they say......I think I'll have to build one after all.....

[Eck]

Is the plan available as a download?

[Major]

Hi everybody.

 

Thank You all for a lot of good advices. Will need to study them carefully to choose best set up. I've got all formers cut, fus is "built" with elastic bands, now just to manage some space inside I'm using parts from old Piper. As far as I've seen dimensions on some websites, there won't be too big difference.

 

@Eck

I don't know, but can copy my one and post to You if You want to. Just PM me Your address.

Edited By Major on 03/02/2012 14:38:06

[Steve Hargreaves - Moderator]

Replikit do a 4 channel kit version for £40 see here called the Sharkfish (do you see what he did there..?)

 

H'mm.....ailerons......interesting....!!

 

Flat sheet wing made out of 9mm balsa perhaps......h'mmmmmm....

[Eck]

Thanks for that, Tom. PM on it's way.

[Big Bandit]

Hi All,

 

After the work that Steve has done, for my electric Sharky, that's the way I'll go. As or Replikit it's a bit over the top, Just take the plan to a copy shop and have it blown up X2 and it's game on, a .15 glow or 300 watt electric in that should eat up some sky . Just need to finish the Super 60.

 

Cheers,

 

Chris.

[Major]

Hi again.

 

Last night I played with my Sharkie. I think I enjoy it a bit too much, as everything goes slower and slower, but still forward.

After I cut formers and servo tray, drilled some holes to allow me to insert all electrics in. Here is a try with Piper's ESC.

 

Just tidn't drill any hole for motor's wireing - I'll wait till part arrives and then do it.

 

Later I have prepared servo tray again with parts from Piper. According to info from GC, TowerPros are a bit smaller than mine ones, but currently I don't predict any problems with it. After all fuselage will look like that

 

All formers are cut from 1/4 sheet, to make servo tray I used 3/32. To the edges of the fuse, like Big Bandid did, added some square 1/8 pieces. I figured that it might be helpful with covering fus with 1/16 sheets. Edges have been sanded after that to gain nice and level surface. Also as You can see, I skipped formers F3 and F4 - I think that construction is strong enough, and anyway it gives me some room to install battery/RX and find correct CoG. In former F5 i drilled some holes for pushrods.

 

Later I did the fin and cut some 1/16 sheet to make some kind of holder on the tail - basically it will be part of sheeting on the top and "platform" on the bottom. Added fairings to the fin which are cut from 1/8 sq and sanded them to achieve triangular shape. After that, have been trying to cut elevator from 3/32 (as same as fin)

 

but my method didn't work as I would like. Maybe it was due to a time - it was already before 7 am as far as I remember and I was a bit sleepy), so just gave up and tried to match together all parts I've already done.

 

And what I've seen really amazed me. For some of You it might be just a glued piece of scrap, but to be honest - I didn't believe that I will do nothing more but wings. Have a look

 

I know that fuselage doesn't look like it should, next time I will remember to study plan very carefully before sticking anything together.

 

 

Special thanks to Big Bandit. Today I have received a parcel from You. Thank You for covering materials as well as some nylon and instructions. Just would like to add, that in my opinion "some" meant a bit less. Thank You very much indeed!! And of course thank You all for good words, support and watching!!

After I came back from the city with plan's copy for Alex, I bought some dope thinner.Probably tomorrow I will (try to) cover wings.It took me a while to go to bedroom after I finished. Just had about 4 fags, watched my little baby and the rewarded myself with few hours of good sleep.

Cheers.

Tom