Topflight P47 Build

[Mike S]

So with the unstarted TF P39 shelved as a future project the TF gold edition P47 gets the go ahead.

After reading the printed manual over the last few weeks I feel this kit is more my level, well sort of. There are a few areas that I will need to learn such as skinning as one example but will teach me the skills needed for the P39.

So the kit also has the cockpit and engine radial kits along with unitracts retracts including a retractable tail unit.

Engine Choice:

It just has to a four stroke engine.

I am currently researching the Laser 80 or 100 but wonder if the laser 80 will be under powered, saying that the Laser 80 was a choice for Andy but he had plans to reduce the weight of the aircraft so maybe the 100 is better for me. I was also considering maybe a saito or os engine but have to look at these.

A few suggestions from Andy have put the Laser 80 to an auw of 11-11.5lbs so the Laser 100 would be a better bet but has a longer stoke of 26.9 over the laser 80's 22.2 and would turn a bigger prop at lower speeds and would also take care of any weight that may get added to the build . The deciding factor will be down to fitting in the cowl without a need to have any engine parts hanging out in the breeze.

The plan suggests 3-1/4" to 3-1/2" wheels to fit easy but 3-3/4" to if built well.  I will need to track down the main wheels and tail wheel in scale for a P47.



 
 

[Mike S]

So the story begins.



Spoke to laser engines today and just happened to speak young ex Srcmc club member John who used to work at Slough rc models. Those with good memories will remember he set up my Raptor 50 v2 when I brought it of Guy. After a good conversation about his latest project (P39 83" model ) he advised me that the Laser 100 is the engine of choice. The laser 80 will not have enough power for 10lb+ model and the Laser 120 will only give around 200rpm more on the same prop as the Laser 100 but at a larger weight penalty. So the Laser 100 is the chosen engine and John confirms it will disappear in to the P47 inverted.

Seconding Andy's advice he suggested reducing weight at the tail end and using smaller servos than standard size to help reduce weight in areas like the flaps and retracts is possible.

Glues suggested to use was Yellow Rocket medium ca rather than pva/aliphatic resin in the tail end.

So today I removed the rear stab ribs and spars from the balsa and cleaned them up.



Thinking ahead about the covering for the P47 I was thinking of glassing but am now thinking of using the idea that Tony Nijus uses and cover in a dull silver film, rub down then spray the P47 in the colours. Once a few flights in and everythings is good then I will weather the P47.

[Russ]

Glad to see you're finally under way.

No Jugs at Slough for a while and now we have an impressive pair to look forward to.

[andyb]

I don't wish to keep poking my nose in, but looking at a .pdf of the manual it appears that there are an awful lot of 1/8" ply formers - this is just overkill unless it's for the firewall, wing bolt plate, wing dowel or retract tailwheel formers; suggest replacing as many as possible with formers cut to the same patterns from two (right angle) laminations of 1/16" balsa.

Also, there was a guy at the Blackbushe show with one of these finished in the box-top colour scheme using silver & black profilm and olive drab fuelproof paint - and it looked pretty good...

One final thing - the carb of the laser 100 will sit much lower than the fuel-tank centreline if it's inverted; it'll run fine inverted but I think you'll probably have to move the fuel tank downwards in the fuselage and/or mount it somewhere between sidewinder (90 degrees) and half-inverted (135 degrees) to get the carb/fuel tank height relationship correct. This shouldn't be a problem though, I think the Laser 100 is exactly the same height as the OS FS-91 that's shown on the plan.

[Mike71]

Hi Mike,

I think you've done yourself a favour shelving the P63 for now. Quite a few extra considerations for a first good scale model and I know that even the full size was reknown for having a few unpleasant flight characteristics

A word on powerplants. As you've already identified the Laser 100 is a longer stroke engine than the 80 and may obviously be harder to cowl as a consequence. What you perhaps haven't realised is the 120 is bored out from the 80 cylinder and therefore has the same low profile. You can always pull that right stick back but an underpowered warbird is going to be a bit of a handful and if nothing else have a bit of a disappointing performance. I've got a 120 in my Eagle and it's a lovely engine, but then again they all are. Granted it is 85 quid more expensive than the 80.

Excuse me digging out my Laser salesmans hat yet again.

Look forward to seeing your progress.

Mike

[Mike S]

No more progress yet as busy at work ordering all these pilots and crews about.

After reading more forum thread builds one thing that I'm considering is building the wing retract positions to the scale position rather than as TF have them in the plan. This will be more work but I may also go the route of scale hinges and hiding the control horns etc.

[Mike S]

Got the green light this morning from she who must be obeyed. I can now put the order in for the Laser 100. This will be next week so should be here by Xmas as confirmed by John at Laser.

[Mike S]

Some progress today on the rear stab.







I next need to sand the ribs, le & te level and then prepare the skins.

[Mike S]

This is defently a learn curve for me.

More work on the rear stab. Made some errors in build so had to work around to correct them but so far so good.

[Mike S]

Been busy in last few days but managed to get the rear stab to 90% finished. Sanded the elevators and stab tips to the plan and dry fitted the hinges to the elevators and fitted to the stab.

Next I need to fit the small ply horn plate to the elevator and fit the u shaped metal rod to connect the elevators.

[Mike S]

Ok great day today. Just ordered my Laser 100 from John at Laser.  After some thought and measurements of other engines it had to be the Laser 100.

[Mike S]

Spent a few hours yesterday building the vertical stab. Its almost finished just needs sanding to profile and hinges dry fitting.

With that set aside I have made a start on the fuse. I had to read the instructions over a few times and look at the formers to work out what TF wanted me to do with them.

After a few hours I have nearly built the top side of the fuse. I made a mistake with the cockpit floor as the instructions called for the two pieces to be glued together. With this done and dried I dry fitted it to the fuse but could not work out how it was supposed to fit. After some thought it hit me that top flight wanted the two parts glued together like you do with when making a skin.

So I made two new floor pieces and fitted them.

Very soon I will need to work out how the Unitracts retracts fit together from the box of parts.

[Mike S]

Last night put a few more hours in on the fuse.

[Gareth]

Looking good Mike.

The vertical stab looks good as well 

[Mike S]

Looking good Mike.

The vertical stab looks good as well 

Hmmm did I not post that photo up. Seems not but will do later.