Topic: 1/3rd scale Sopwith Pup

Just started cutting wood up for the replacement fuselage to go with the wings that Alan H gave me.  Wings will also need some work but are a good basis to do a quick and dirty no scale detail at all 1/3rd scale (scale or size?) Sopwith Pup.

The longerons are from a nice piece of 2" X 2" timber that's been leaning up against my garage outside for the past year.  Once I planed off the white paint I found it had very nice straight tight grain between the flippin screw holes............. it's reclaimed timber    Sliced it up on my circular saw and managed to get out all 4 longerons the cabanes and stringers for the top of the fuselage rear.  The original fuselage ply side cheeks appear to be a chgeap birch ply but after a message from Ian and also Alan it seems it's cheap USA liteply.  Booga I already cut em from nice quality birch so am waiting for new material (yes I do buy new sometimes  ) from SLEC.

I have cut up what I can and made the side ladder frames, the 2 X bulkheads and the rear ply top and bottom fuselage bits that the tail plane and skid attach to.

Just got to see if I can carefully dremel out the glue holding the cabanes to the top wing centre section otherwise I will be making that up to........ the original also needs work as it's a bit ropey.

Still need to get some wheels but £30 for the Mick Reeves ones hurts a bit, maybe I will make some ply ones with automotive black water pipe as tyres.

Ceejay is supplying me with a lovely new spun cowl as the one with the old airframe is to short and has a lump cut out of it at the bottom.

Subscribed.... What engine will ewe use Shaun?

It will be my G38 that was in my Cristen Eagle with a reduction drive I believe the firewall does not need moving backwards for that set up?

It will be my G38 that was in my Cristen Eagle with a reduction drive I believe the firewall does not need moving backwards for that set up?

If you need any photos or measurements let me know. Happy to be snappy....

If you need any photos or measurements let me know. Happy to be snappy....

Well.............. true lengths of the undercarriage piano wire would be helpful cheers    I guess 1/4" piano wire is enough for the axle.  I cant decide whether to make 2 axles with pivots on their ends (centre of axle) or a single axle pinching it in the centre same as I did with my SE5a this way if a bungee does give way it affords you a degree of suspension still but does rely on the 1/4" axle being able to bend.

Kewl, I'm in for a looksee 

Now, about this detail thing (lack off).......... 

Muds

PS The offset Tony Clarke Reduction Drive is 175mm from firewall to face of prop driver.

Now, about this detail thing (lack off).......... 

Muds

PS The offset Tony Clarke Reduction Drive is 175mm from firewall to face of prop driver.

Thanks for the measurement I will check that out and see where the firewall needs to be 

ref detail......... none other than a pilot if I can get one and a home made gun nothing else it's purely for me to get some experience with building handling and flying 1/3rd scale, any detail will be in the Bristol Scout maybe later this year.

Opening post and first paragraph,Shaun writing,"And no scale"! Yer right, who else believes that? 
You can't help it mate once you get the balsa dust up your hooter
Albert

Well.............. true lengths of the undercarriage piano wire would be helpful cheers    I guess 1/4" piano wire is enough for the axle.  I cant decide whether to make 2 axles with pivots on their ends (centre of axle) or a single axle pinching it in the centre same as I did with my SE5a this way if a bungee does give way it affords you a degree of suspension still but does rely on the 1/4" axle being able to bend.

Hi Shaun.

Mine has 2 axles, each  6mm pivoted in the middle and sprung at the wheel end.  It's has three seasons of flying and the 6mm axles have a habit of bending where the bungee is wrapped around. It was well bent when I bought it.The advice now is to sleeve these with 8mm tube which has proved on Ceejays Pup to be more relaible and doesn't bend...

The axles are 205mm long from the centre of the bolt to the inner face of the wheel.

The front uprights are 315mm and the rears ar 330mm. Probably not scale but looks ok..

ref detail......... none other than a pilot if I can get one and a home made gun nothing else it's purely for me to get some experience with building handling and flying 1/3rd scale, any detail will be in the Bristol Scout maybe later this year.

Good move, makes for easier upkeep and stress\free flying... Good move Shaun but somehow I think you'll do some more..

Only a little more eh Shaun.


 

Watching this one mate
Good on you.
As usual it will be great.

One mod ref the UC. We have attached the flying wire brackets to the UC where it fixes to the fus. I tacked my ones with the Mig welder. Will get a picture tomorrow for you. Makes for much better anchor points for the flying wires.

Si

This is going to be another goody

quick and dirty no scale detail at all 1/3rd scale (scale or size?) Sopwith Pup.

Yes, right.   Maybe just a little joystick for the pilot to hold .......

Looking forward to it Shaun.

Alan

There you go mate. Much better than whats shown on the plan. I leave the wires attached to the brackets all the time. That bracket holds the piano wire u/c to the fuz as well. There are 4 in total .



Si

Much better than what's shown on the plan.

Si

I like that rigging plate Simon and a picture is far better for me than any words    BUT............ single wire for me this is a sport aircraft purely for experience and I'm going to use quick ling 3mm clevisis 

I hope by the time I build the Bristol Scout to be the owner of an old Myford 7 so I can make up all my own rigging terminals    It's been promised to me for about 3 years so I'm patiently waiting for the go ahead to pick it up  .

More tree has been ordered from SLEC but they are out of 1/8" ply so will have to wait till next week before I can do much more.

I guess in the mean time I can be chopping away at the epoxy to get the top wing centre off the old cabanes 

I already have a length of Diatex 1000 and just about enough WBC paint I may have to place an order to Skycraft for some dope but that's a ways off yet.

No problem with 3mm clevis Shaun. They will be fine.
I would still use twin wires on the rear ones with the single on the front ones as per full size. Its only two more wires to make after all.

Si

Mine uses 3mm Clevisses which makes for a rapid assembly and de-rigging.

Flying wires are doubled front and back and landing wires are singles..

Thy need to be checked though as the pins wear through quite quickly..

No problem with 3mm clevis Shaun. They will be fine.
I would still use twin wires on the rear ones with the single on the front ones as per full size. Its only two more wires to make after all.

Si

I thought they had twin both front and back on the top wing    I will worry about that bit once I come to it.  I just managed to get the top wing centre section off the off fuselage cabanes intact and there is just enough give in them to let me spring them out and slide in to the new fuselage (once I get it together) so that saves me trying to dig out all the old glue and potentially knacker up the wing.  Having said that the 1/4" square on the top leading spar has a repair which consists of a butt join    also need to replace one rib.  There are several ribs need replacing in the wings + 1 spar is very soft.

I too would fit doubled flying wires, adds so much to the safety factor and it makes it more scale

The routes for the flying wires on the BUSA kit has to be the worst bit of design on the model. Fixing the wires to the U/C legs give a strong continuation of flying loads between the wings instead of simply pulling the wires through the fuselage sides. Shaun, are you thinning the wing section down? On mine, and the Ceejays, the wing was thinned so much the top spar was removed, without effecting the strength.

Ian.

The rib that carries the interplane struts was slimmed down more so it didn't show through the covering. Whilst on the 'making you do it more scale thing', are you farting about with the rear end too? Sectioned tailplane, gap under the fin etc It takes little time and makes the model even more practical since everything is removable easily.

Ian.

Ok ok I will fit double wires   

Yup the continuation of stress/pull makes perfect sense I will go with that cheers guys for the advice this tried it and done it knowledge makes all the difference.

The wings are built and just need repairing so I wont be thinning them down they will stay as per plan (unless advised otherwise).

The rib that carries the interplane struts was slimmed down more so it didn't show through the covering. Whilst on the 'making you do it more scale thing', are you farting about with the rear end too? Sectioned tailplane, gap under the fin etc It takes little time and makes the model even more practical since everything is removable easily.

Ian.

Booga posted again before I was able to reply!

As above the wings are made so no thinning will happen there.  I like the idea of being able to remove the tailplane for storage and transportation a few more details on the socket and pin affair would be helpful .................... and no not for scale purposes!  Honestly I just want to a relatively quick build for the 1/3rd size experience before I build the "the one".
What about 1/4" square cross bracing on the under side of the fuselage it's not shown on the plan but would add a lot of torsional stability to the fuselage without much weight is it worth adding it?  Could be 3/16" square set back 1/16" so it doesn't show.

Wheels.................. Mick Reeves or make the from ply and car water hose?

Stuey, does a piece of brass tube over the 1/4" piano wire really make that much difference?  I will be soldering some on anyway so I can cross drill the ends for split pin wheel retention.  Also thanks Stuey for the heads up on checking the clevisis frequently I'm just ordering 100 x 3mm ones from a private seller 

I will get a picture of what I have so far but not a lot to see, side frames in 1/4" square, 2 X forward fuselage frames in 1/8" liteply and the wing top centre section removed from the old fuz and cabanes cleaned up.

Love this knowledge base on the RCMF and the people willing to spend their time helping others 

Was just looking at some detailed pics of the Sopwith Pup at Shuttleworth and it doesn't use  double streamlined wire bracing, but single cables only. Just thought it might save you a lot of work?
Regards,
Tentpeg. 

Hi Shaun, at least you won't show me up as mine is std sections on the tail and wings too.

My tail can come off as standard, it's four quick release clevisses and four self tappers.... Dont do it though as it fits in the trailer quite well without...

On the u/c axles, the suggestion is 1mm dia steel tube to go over the 6mm, giving 8mm overall. According to ceejay it makes all the difference... On my Pup with the 6mm, the axles will bend just wheeling it across a grass strip!

Thats no way of getting out of the section mod Shaun, Ceejays wings were already built too!!

Ref. the tail surfaces. The tailplane had a liteply tongue at the front (on the underside of the tailplane) that slotted into a liteply former on the fuselage. Two 3mm bolts at the back and the bracing held it on. The fin had a dowel as a rear post that slid into a brass tube sternpost on the fuselage. This sternpost had two straps soldered to it to screw into the top and bottom longerons. The front fixing for the fin was also dowel that slid into a tube on the tailplane. A bit of this tube was also on the dowel to give a positive shoulder for it to sit against. All that held the fin on was the rigging. The rudder bottom hinge had a tube soldered to the sternpost and wire in the rudder, so as the fin and rudder was slid into position, the wire could be located.

Hopefully the pics will explain more betterer

Ian.

Was just looking at some detailed pics of the Sopwith Pup at Shuttleworth and it doesn't use  double streamlined wire bracing, but single cables only. Just thought it might save you a lot of work?
Regards,
Tentpeg. 

The Shuttleworth Pup is a re conversion of a Sopwith Dove or it might even be a replica

Not that it makes any difference really, but double flying wires are definately safer if using clevis'.

Its not just about transport, removable bit make it much easier for servicing and maintenance

Ian.

............... much easier for servicing and maintenance
Ian.

What's that then?

What's that then?

  I didn't mean it that way, but now you mention it

Ian.

I didn't mean it that way, but now you mention it

Ian.

I guess servicing is what you need to do once you have actually built something...? 

Rather disappointed with my time spent today on the top wing centre section.  I got the struts all cleaned up nicely and another rib fitted only to find another rib broken + the rear spar which is only really to fill the shape out as it's 1/2" x 3/16" balsa is boogered.  Then I slide on the wings and I forgot there is 1/4" misalignment I was going to knock out the dowel enlarge holes and make good with wood washers but why the step was it always wrong or has the rear of the centre section drooped............ dunno may make a new centre section from new.  A lot of the balsa seems almost rotten very soft and does not accept glue :(

Top spar inboard soft as poo and repaired 



Centre section spar (with someone's attempt at a repair! not mine) which I removed and replaced with new maybe a waste of time now



Wing ribs had Celotape on the back and nonails on other side great repair 



Single rib where the interplane struts attach.

Found where the problem lies after removing the covering from the other wing which has also been repaired (I use the term repaired loosely) the rear of the wing appears to kick up.  The rear portion of rib has been replaced but incorrectly aligned I'm now wondering if any of this is worth the time putting in to it.  I'm not going to build new wings as well as fuselage but repairing the wings will take as long as building new and will always be a repaired wing.

New rib and spar fitted to centre section



And that trailing edge of the top wing sorted out, it's actually better than it looks in the picture no more than 1/32" high now.

One rib ready to glue in place an a spar almost in ready to glue

BUT





Whilst repairing one wing I stepped back on to the other 

Seriously considering bringing this rebuild to a halt now and giving up.  The wood is either brittle or almost feels soft like rotten and I'm chasing break after split after crack.
As I wanted a quick build I'm not going to be cutting out new ribs etc and making new wings just to much time involved + materials cost.  Cant afford a kit as well as reduction drive wheels and all the other gubbins and like I said I'm just have it in me to do a long build.  If I made new wings I would then want to make a proper job of it and do the detail............ to much time.

Looks like my 1/3rd size experience will have to halted for the foreseeable future unless I see things differently tomorrow but being honest with myself the amount of either chasing breaks and rot or time making new wings wont alter.

If the wings are that bad then give up on them, but I would build a new set as really there is not too much material, and won't take too long. As for adding detail, add as much as you feel like doing, it will be good practise for the next one.

Keep going 

Steve

Before making a rash judgement I though I better check out the bottom wings.  They are in much better condition but will need the ribs cutting which hold in 1/4 scale servos which are held by no nails or something.
Top wing spars = balsa
Bottom wing spars = redwood

Is that normal?  If I only have to butter up the top wings to be serviceable and a couple of ribs on the botton maybe the rebuild is back on   

Right after finding the bottom wings are in better condition and the top wings have stopped creaking/cracking and making snapping noises every time they are picked up I think the restoration is back on my apologies for posting prematurely earlier.

Materials have already been ordered from SLEC so I hope they will turn up some time next week, they would have been here today but they are out of some of the ply and it's silly to do two deliveries so I'm happy to wait.
Once I'm happy all the repairs are done on the wings I will give them a coat of dope on the surfaces ready for the Diatex or Koverall and may cover them sooner rather than later as the ribs are vulnerable to breaking as they are.  As long as I do the little modification as suggested to the bottom wings so the rigging (of 2 wires  ) can go through I don't see an issue with them being covered.  Oh I will have to make the servo mounts and doors 1st I guess.

Glad you are back on it .
Keep it up.

Si.

Top wing centre section is completely repaired but now there is only just enough spring in the cabanes to be able to spread them to into the slots which will be on the fuselage (I hope).  I thought now was a good time to get the underside covered as it will be a sod once it's on the still to be built airframe but the cold is not helping me as the dope is slow to go sticky today.  I'm not that confident it will hang on the under camber when I shrink it if it proves to be an issue I will re do it but pva on under cambered bits.

I've not shrunk the Koverall yet I'm letting the dope cure completely before I do.  In the mean time I though I would knock up the tailplane which is now done so it's elevators next.
That rear end looks very nice Ian and I do like the scale raised fin but for a non scale Pup is the effort worth it or should I just go for the Q&D fin glued straight to the tail plane?  It could still come off as a complete unit for storage and transportation just less flat packable.  My trailer is only 4' wide so by the time you take into consideration the roller door runners there is a couple of inches spare to get the tailplane in so I suppose it could be glued straight on but does not look a big job to make it removable.