Airdrome Airplanes Sopwith Pup Project

RAF56_Ball · 4 September 2009, 11:38 PM

My apologies to all, I have been up to my eyeballs with work (again apologies for using 4-letter words in a family forum)!

Was about to mount my firewall, but the guys here at the hangar all came unglued. “Aluminum?!?” “Are you crazy?” “Glenn, I’m sorry but that is just foolish”. Those were the nice comments.
I figure all of the brouhaha might be settled by putting a heat blanket on it. No stainless steel 0.015” or even less than or equal to 0.025” is available in the area, (the thinnest I found was 40 thousandths – about three times the weight, a bit pricey, too) and ACS wants almost twice the cost of the sheet to ship it (oversized-package pricing costs).
I know safety is the concern, but the fire ratings are based on being at 17-18,000’ and needing to get down and land in 15 min or less. I doubt I will be over 10,000’ ever, and would need less rating. But I am looking at 2000 degree batting, which with the standard firewall, should be just fine.

So, just updated the site. Some of the new pics with my new cell phone (had to replace the old one as it was dying) are a bit yellow/green, and focus is a pipedream. Still, they should satisfy the FSDO when it comes to the inspection.
I just mounted my center wing panel after taking off the gear, tail feathers and building wing trusses. Hope to have wings mounted by the end of the Labor Day weekend, with ribs attached. Am doing all this solo, although tomorrow may have help from youngest son.

The prop came yesterday. Culver’s makes a beauty, gents. The dark stain is primo. I am trying to make my aux tank, but having trouble learning to weld sheet. Do okay with thick stock, but the 0.050 is a bit tougher.

Back to it in the AM, so have to get some sleep.

Blessings to all!
Chip

RAF56_Ball · 4 September 2009, 11:43 PM

by-the-by, here is an intersting link.

Index

This gent is planning to build a Pup also, painted in RNAS 3 colors most likely, and try to take it to the 2011 Vimy Ridge commemorative event. Am considering joining him and starting a campaign with some donors here in Wausau to get us some funding to ship the birds over. Could be quite an adventure!

John McKenzie · 5 September 2009, 12:55 AM

Hi ...SNJ5...Refering to your enquiry regarding streamlined wires ; I fear that the cost of these could almost double the cost of your project..(no including the motor ).in terms of materials or kit cost .....You'd obviously want to get a quote to be certain * however expect "several " thousand £ .

* for full details of address /e-mail etc....for " Bruntons " who make them ..go to Replica aircraft ,...Streamlined or bracing wires...posted by Leatherhead...see my reply.
Sorry , dont know how to post a link .....hope you find it

Regards John.

(PS ..I'll look again to try to find it )

snj5 · 5 September 2009, 02:47 AM

Chip - brilliant work. It is more exciting and inspirational with each update.

John - thanks for the post. I have not priced them yet, but they surely can't be worse than the period instrument prices I am finding, or what having a wicker seat made costs.

Chip and I were also having a chat about using a rudder bar or not, and I brought it up on the Baslee builders group. Modern airport environments do heavily favor having some sort of brakes (to go with the tailwheel). Philosphcal discussion aside, it seems that with a bar the choices would be heelbrakes (a bit awkward) or the British hand brake with the rudder controlled differential valve, a system I have never flown with only having read about it in magazine articles.

Do you or any other folks that have flown the stick hand brake with rudder differential (e.g. Chippie or Moth) have any comment or advice for those of us over here in the colonies raised on pedals?

Many thanks!
Russ

drrivah · 5 September 2009, 04:58 AM

Chip:
Inspirational photo-documentation on your build.

What are dimensions of the Chen Shin wheel hubs (width of hub and ID)?

Thanks.

-pete

hank jarrett · 5 September 2009, 04:44 PM

The principal reason for a rudder bar over rudder pedals is the load paths in the fuselage. You may notice that planes with rudder bars use much smaller rudder cables. That is because large rudder cables aren't needed with a rudder bar.
With rudder pedals when you press on both pedals (and believe me, you can put a LOT of force on those pedals) the loads are passed through the cables and reacted by the rudder horns and the rudder hinge.
With a rudder bar when you press on both sides the loads are reacted by the pivot pin in the middle of the rudder bar. The cables are sized by the air loads on the rudder, not our size 12 clod hoppers.
The use of rudder bars was a logical one by early designers. The heavy structure to react the pilot foot loads is concentrated at the front of the plane and everything aft of the cockpit can be lightened, the rudder hings, control horns and even the longerons are lighter. The critical design load for the tail can actually be a pilot in a panic jamming both feet down at the same time and it is possible to actually deflect the whole tail cone with that much force. With a rudder bar, all you have to strengthen is the bar mount. Only the difference between the pedal forces passes to the cables and that is limited by the aerodynamic and hinge friction loads.
It really scares me when I see a GL Nieuport with rudder pedals. The first thing I expect to see a failure in is the rudder horns, after that anything goes, including buckling of the longerons. Graham was a pretty good back yard engineer.
Hank

snj5 · 5 September 2009, 06:06 PM

Excellent explanation - thanks!

snj5 · 5 September 2009, 06:11 PM

Quote:

Originally Posted by John McKenzie

* for full details of address /e-mail etc....for " Bruntons " who make them ..go to Replica aircraft ,...Streamlined or bracing wires...posted by Leatherhead...see my reply.
Sorry , dont know how to post a link .....hope you find it

Regards John.

(PS ..I'll look again to try to find it )

Here is the American distributor:

Steen Aero Lab - Bruntons Flying Wires

I was speaking to an older seasoned pilot today who remarked that the streamlined wires indeed made a noticible difference in speed in his experience. Any others?

mustang · 5 September 2009, 06:53 PM

Quote:

Originally Posted by snj5

Chip - brilliant work. It is more exciting and inspirational with each update.

John - thanks for the post. I have not priced them yet, but they surely can't be worse than the period instrument prices I am finding, or what having a wicker seat made costs.

Chip and I were also having a chat about using a rudder bar or not, and I brought it up on the Baslee builders group. Modern airport environments do heavily favor having some sort of brakes (to go with the tailwheel). Philosphcal discussion aside, it seems that with a bar the choices would be heelbrakes (a bit awkward) or the British hand brake with the rudder controlled differential valve, a system I have never flown with only having read about it in magazine articles.

Do you or any other folks that have flown the stick hand brake with rudder differential (e.g. Chippie or Moth) have any comment or advice for those of us over here in the colonies raised on pedals?

Many thanks!
Russ

I have flown the Fairey Battle, Spitfire, Vampire, Meteor, Canberra and Bristol Freighter with differential rudder bar and hand brake on the control column. The Chipmunk had the same type rudder bar but the hand lever was mounted on the left side of the cockpit, The tiger Moth had no brakes unlees retrospectively fitted. I have also flown P40, P51. C47 Dakota, Wirraway, Winjeel (military) and many other light General Aviation aircraft fitted with pedal brakes.

I cannot say that I preferred one system over the other. There was no problems in transitting from one to the other, even on succesive flights.

I have fitted a tail wheel to the Moth which incorporated a brake operated by a hand lever on the stick. The braking was not particularly effective but better than the tailskid. However, the steerable tailwheel was a major advantage on a paved runway. It was also very easy to replace the wheel with the tailskid if operating off a grass airfield. About ten minutes.

This system may well be worth considering for light replicas.

Mustang