100 psi is about a 1/2 inch

Thanks very much Ron. That helps a great deal. I might start making up the mounts this weekend.

Originally Posted by Gree

Really Good 3 Views
Hey does anyone have any really detailed 3 view drawings of the bubbletop P47, showing rivet patterns, access panels and panel lines accurately?

I want to locate an access hatch for my air fill valve in a scale location and my 3 views are all pretty tiny.
[/i]

Gree hows this one??

http://richard.ferriere.free.fr/3vues/p47_d25_3v.jpg

Great built; keep up the good work

Stu

This is not quite a 3-view, and I'm not even certain how exactly scale these models are, but one resource I frequent often is the Hyperscale models page. This is a collection of highly-detailed static models built by some very talented modelers. These guys are typically much more interested in scale accuracy than the RC crowd. There are a slew of P-47 models if you look in the "P" section. I'm certain you can find a photo or two of the area in question...


Luke

Hey thanks Stu and Luke. Lots of good reference there. I was hoping to be able to mount the air filler in a forward panel, but I am not sure if they will be big enough. I can't use the one on the left side under the cockpit opening because my cockpit kit will be in there, and the hatch I nominated above will also be tricky because I did not think ahead and it's hard to work back there.

I'll check these out, do some measurements and see how we go. Thanks a lot, always appreciated.

Thanks to Luke's post to that modeling site, I stumbled upon a few more ideas for paint schemes... I am not sure now what to choose, but I think I am leaning away from my original choice somewhat. Something more unusual may be the ticket...


Also found a good model that really shows the hatches well...

Building the Hatch and the Mounting Recess
Well I decided to go for a hatch on the top front of the plane from the 3-view provided by battlestu - thanks!

This panel proved perfect, but was bloody hard to fit due to me having already sheeted the entire fuse and of course having glued the servo tray in! Talk about not thinking ahead! Ah well...

I made a glass panel the same way as I did with the tailwheel doors - 5 layers of 6oz and 1 layer of 0.25oz. Once the panel was cut free from the plane it was time to make the mounting for the fill valve, the pressure gauge and an emergency cut out switch for the main battery power. You can see this best in the pictures below.


Finishing the Air System
I also finished hooking up all of my air lines, routed them through the small frame supports I made in the wheel wells, and installed the retracts.

It was a pretty exciting moment as it would be the first time that my retracts would move under their own power!


F#@%ing Air Valve!!!
Well I hooked everything up carefully, temporarily sat the wing on the upsidedown fuse, and got ready to see retract magic.

I screwed my Robart hand pump into the fill valve, and began to pump up the system. I was met with a horrific 'hhhhhhiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiisssssssss' sound coming from the fill chuck. Unscrew it and the system holds air perfectly. ARRRRRRGGGHHHHH! All of my airline joints as tight as a drum and I am brought low by a brand new part!

The fill chuck o-ring leaks like a sieve. I tighten the chuck up as far as it will go and 'hhhhhhiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiisssssssss'.... I can only get 20psi into the tank.

Soooooo ticked off!

The o-ring on the fill chuck seems to be able to slide back form the threads on the chuck a bit less than 1mm, is this normal?

Has anyone else had this problem with their Robart fill chuck?! I am so close to ticking the retracts off the list this is driving me nuts -so any ideas about how I can fix this greatly appreciated.

Well its always best to walk away when things are going wrong. I did a little research last night and found a comment in a forum somewhere about a Robart pump not holding pressure, and someone recommended putting a little oil on the seals inside.

Well I thought I would give it a go and ran some olive oil of all things all over the o-ring on the fill chuck.

What do you know... seals tight as a drum now! Jeeze talk about a simple fix! I am now a very happy camper, except for the fact that when the mains go down, the tailwheel goes up! Ah well some tube reversal ahead for me, but overall the retracts are done and working very well. The system has held 100psi for about an hour so far, so I think we are good to go!


A couple of videos of the retract operation...

Robart Retracts First test (0 min 29 sec)

Robart Retracts First test part 2 (1 min 43 sec)

EDIT - Actually I just realised I plumbed the tail wheel according toRobart's instructions. I twas just that usually retracts extend their pistons when the wheels go UP, but the tail wheel cylinder extends its piston which pushes the tail wheel DOWN. SO following instructions is not always the best policy!


Next the bomb release mechanism and hooking up those tail wheel doors!

Looks Great bud...
it's always fun playing with retracts
shoot you'll be flying it by spring

Ron

Funny thing is no matter how slow I set the 'down' valve, the retracts just clunk down very fast. But it works so shouldn't be too picky!

Yeah, retracts are sweet, but aren't they fun!? Seriously though, looking good.

Eric

"Funny thing is no matter how slow I set the 'down' valve, the retracts just clunk down very fast. But it works so shouldn't be too picky!"

Are you useing the red adjustable valve from robart? the 167vr?
I hate the valve with a passion..lol... I've used like six of them over the years and they are hard to get working right.. I've also had the adjusters loosen up in flight ... one even fell out

I like the blue non-adjustable valve better.. then I use the restrictors to get the speed right... it seems to be a much better setup

but if you have it working you'll be fine.. just make sure you have the lock nuts tight...

Ron

Yeah I am using the red valve. Don't worry I already worked out that the valves will unscrew themselves if you look at them funny. I tightened up the lock nuts pretty good.

It just seems when you hit 'down' it goes fast no matter what you do. I may still try tweaking it. I was thinking it may be slowed in flight by the air stream pushing up against the wheel fairings as the wheels try to come down.

It makes sense to me, since the only reason it goes slow going up is because its fighting gravity. If I hold the wing upside-down and raise the wheels they thunk it very fast too.

Completing the Tailwheel Opening/Closing Mechanism
Funny, this was a job I have been dreading, but it turned out to be quite easy!

I bought some Dubro micro control horns, drilled holes and mounted some 2/56 ball links. I also made up some adjustable links from ball link connectors and threaded rod. Easy peesy!

The horns were epoxied in place on both the doors and the tail wheel itself. I had to think about the geometry and placement to ensure enough travel to open the doors wide, and to close them fully.

I have not hooked up the air yet to test both doors out, ran out of time, but looking forward to it!


Here is a video showing one side working manually to give you an idea...

Manual Test of Tail Wheel Door Mechanism (1 min 7 sec)

EDIT - Here is the video of the system all hooked up and working. Need to adjust the gear down speed a bit more I think, but all in all works perfectly. I am a very happy camper! Wish all parts of the build went this smoothly! I'm really chuffed!

(oh, and the tailwheel now operates the right way 'round too!)

Finished Tailwheel (0 min 34 sec)

Great Store and Service
A quick shameless plug... I have gotten a lot of parts, and excellent service from Peter Smith at Anthony's Pete-n-Planes www.petenplanes.com.au. Great store, fast post and like I said, great service. Pete will go out of his way to answer questions, and even ordered parts for me that weren't in catalogue in record time. Check out his store! Plug over...

Time to Dirty it Up a Bit
Didn't get much done over the weekend, just routed the cables for the pylon bomb releases, and weathered one of the wheel wells in preparation for sheeting the bottom of the wing...

Some pics below to give you an idea. Have to get myself an airbrush before it comes time to paint the outside of the plane...

I have to work out what I am going to do about the inner gear doors though before I sheet the wing... A problem I have been putting off...