Compartment Behind Classic Radial Engines?

[Lionheart]

Hey all,

Im doing a classic Radial powered GA plane. She has a access door behind the radial engine.

Anyone know what is in one such compartment? Any pictures of a typical compartment? I think the Stearman biplanes would be similar if they also have such compartments/access doors.

On this plane, I asked the man who restored it, and he said 'access to the back of the engine. However, this one has a firewall behind the engine, and also, on the Warner Super Scarab engine, she had the Mag's and Starter mounted on the back of the engine, directly bolted on, so those will not be in that compartment, but ahead of the firewall.

So, just wondering if anyone might know. No pictures exist of such a compartment.


Many thanks for any help on this.

Bill

[stiz]

could be used for access to the connecting wires/tubes etc from the cockpit controls to the engines? inspection panel for firewall??

[OBIO]

In some cases, I would imagine that the battery would be in this area, possibly the oil reservoir/filler cap perhaps. Maybe a small cooler for carrying the trout home from the lake?

OBIO

[pilottj]

its access to feed the hamster on the wheel :d

Like Obio says, likely access to battery, inspection of components.

Cheers

TJ

[Bomber_12th]

It is typically known as the "accessory compartment", providing access to things like the rear 'accessory' section of the engine, the engine mount, the oil tank, possibly the batter/generator, and all of the plumbing and 'hook-ups'. Here is a view showing what this area looks like on a Stearman:

http://www.flickr.com/photos/nightbeacons/2541025350/sizes/l/in/photostream/
http://www.flickr.com/photos/n185ll/176282024/sizes/o/

Being as such, this is where most of the 'business' takes place.

This picture of a Warner Super Scarab-powered Ryan, sort of gives a hint of what has to lie behind the engine:

http://www.eaa.org/news/2009/images/ryan_engine.jpg

[TeaSea]

Really not much more different than what's behind a standard in-line engine. You still need to get to the oil pump, aux fuel pump, filters, motor mount, etc.....

[Bomber_12th]

By the way Bill, have you seen this photo journal? When I saw it for the first time, I had even mentally noted to myself that this would be an excellent future project - I am so glad to see that you are doing it!

http://www.maxair2air.com/10AIR/Skylark/01.html

One of the photos simply showcases the art-deco styling of one of the nav-lights - just amazing!

[Barvan40]

That is the compartment where Piglet keeps his dog treats. :kilroy:

[warchild]

One difference i noticed. both the stearman and the pasped have gas caps in front of the windscreen.. Now, if i remember right 9 which is sometimes debatable) a long time ago before designers had any common sense, they put the fuel tank in front of the cockpit.. Is this the case or am i completely off base???

[norab]

The fuel tank in front of the cockpit wasn't always a question of common sense Warchild, sometimes it was on purpose, for instance in the classic J-3 Cub "Visible fuel gauge is integral part of gas tank cap; it will not show number of gallons but will show proportion of fuel in tank by length of rod which extends upward from cap. A full tank of 12 U.S. gallons will be indicated by 11 inches of rod extending beyond cap. Keep gas gauge rod clean and smooth with crocus cloth for accuracy and freedom of movement. "

6891
While you are flying you simply look out your windshield and the relative height of the rod tells you how much gas you have left. The last inch or so at the top of the rod right under the " L" bend is painted red to let you know that it's time to look for a gas station

[Piglet]

These are all good , logical guesses. But to be honest Barvan 40 has the one true answer!:icon29:
But of course one still has the ready locker for treats in the cockpit, for easy transfer to the dog.
On some Piper Saratoga types, it is a baggage locker.

[srgalahad]

Actually Pam, it was common sense (maybe not ultimately wise). A lot of the engines have a low-mounted gravity feed carb (no electrics=no elec. fuel pump and mechanical pumps add complexity and weight). Putting the fuel tank that close could keep the tank in a tail-dragger above the carb while at rest. Wing tanks would too, but then you have longer fuel runs, multiple fittings and bends in the lines (potential breakage or leaks), routing through the cabin/cockpit (leaks again) and some potential for asymmetric issues.
You know.. design compromises...:wiggle:

[Ken Stallings]

I would guess the oil capacity for that kind of aircraft is around 15 quarts -- not that large. So, I doubt such a large door panel (assuming you outlined its actual size) would be needed merely for access to oil and fuel lines and the tank.

My best guess is it would be a baggage compartment. That would be a good place for one since it would be close to c/g.

Do you know where the fuel tanks were located? If in the wings only, then no need for that space between firewall and cockpit to be that large -- so that means a prime space for baggage.

Cheers,

Ken

[Bomber_12th]

I can't really imagine there being space for baggage - that area, as far as I can consider, has to be filled with motor mount, oil tank, plumbing, and what have you. If there were to be a baggage compartment, it wouldn't be that close to the front of the airplane I'd suspect, and would instead have been placed more likely on the other side of the aircraft only, behind the cockpit, if there were to be one, where it could more easily be accessed. I also think, that by the answer Bill got from the restorer, that if it was a baggage compartment, that is what he would have stated it as being.

To have a hinge on those access panels is quite novel - that way you don't have to spend time un-doing a bunch of fasteners to get access to inspect that area of the engine-accessories. The Stearman is the same way.

I know it is a Stearman, but I imagine it must look similar to this...note that the design of the aircraft tapers up to meet the engine from just behind it, with a fire-wall like surround, but the engine mount extends back to the true firewall, and when fitted out completely, is filled with all of the plumbing, tanks, filters, and else that must be in place.

[Lionheart]

Hey guys,

Many thanks for the input and all.

Bomber 12th has it right, and many thanks for the pictures.

In those pictures, you can see the components behind the engines were 'in' that compartment. On the one I am making, the engine has all its ancilliery bits ahead of the firewall, and so none of those are in the rear bulkhead compartment. So yes, Oil resevoir, battery, etc, were in there. I didnt know it would fill that fast though. From those photos, you have NO room for anything else. Wild..

Fuel tank on the Pasped Skylark was in front of the instrument panel, fuel cap on top in front of canopy structure.

Ken, I had originally thought the same, that it was a storage compartment for a dufflebag or something, but nope.. Its behind the seats (officially), and not enough room (according to the man I talked to that restored this plane) for any cargo.


Thanks again Bomber for the photos. Finding such photos was harder then finding photos of penguin fangs on the web...

Oh, and yes, I had seen that website John on the Skylark. Some excellent photos. Especially of the instrument panel, and those cool antique wingtip lights, casted in a teardrop shape. Finally tracked those down...


Bill

[Bomber_12th]

I'm sorry I couldn't find pictures of a Pasped Skylark to see what it really looks like per that particular aircraft, though I tried hard. :)

Might need to make a photo-request in the vintage aircraft section of Warbird Information Exchange forum-site, as I am sure a member or two will have photos to share, since several are very involved in flying/restoring/operating vintage 1920's/30's aircraft, and have likely been around the real-world one.

[fliger747]

There is a saying about radials, land and fill the oil and check the fuel. Many of the larger radials have huge oil tanks nounted in the nacelle. The F4U could hold as much as 195 lbs of oil in the supplimentry tank!

Cheers: T