Thorp Air Command - T18.net

I ran WnB for two fuel tanks below the baggage compartment floor. It worked ok at 20 gallons. Of course, that was with a car engine up front.
Cubes

Like I said before , if I had the chance I would put in the larger DR main tank !

RB

Of all the solutions for increasing T-18 fuel capacity, I like David Read's. Forty Gallons is all I would ask for. If you need more than that, David's scheme won't work for you. But with the modern instrumentation available, a shallow instrument panel design can expand the space available in John Thorp's original design and adds the benefits of single tank, gravity feed, minimal CG impact, simple plumbing, etc.

GG

Exactly what I said !!

RB

I submitted an engineering request for a fuel bladder in the outer wing panel as I mentioned.
We'll soon know how spendy and irresponsible it is...

_________________
Scott Emery
EAA Chapter 326
T-18 N18TE

Dave Dack @ ATL the fuel cell company got back to be today with a quote for the fuel tank(s).
Kinda spendy, about $600 per gallon!

Well, that's the first bid...maybe Race car or Boat....

_________________
Scott Emery
EAA Chapter 326
T-18 N18TE

If I didn't go the DR tank route , I would put in a single thin profile aluminum race tank on the baggage compartment floor . Single in tank pump to fill the main tank . 15 + gallons ?

RB

I hear you RB.
before I got on the fuel bladder idea, I'd been designing a con-formal wing tank to fit close under the wing join, similar to the Hunter 'non-drop' tank, but looking more like the engine pod of an Me-262.
I picked up some .063 5052 Aluminum sheet and some HTS-2000 aluminum 'welding' rod:
https://www.aluminumrepair.com/hts-2000 ... azing-rod/
Hoping to make a warp-free brazed external tank.

The baggage under-floor tank seems a lot easier, especially the plumbing.
Here is a cool Newton filler cap with angled neck for a side-of-the-fuselage filler
https://fuelsafe.com/a36nl44lfk-flush-c ... e-flapper/
This filler has a vent point that is above the tank, and being at the side of the fuselage, could loop up to the upper longeron like an RV, then through the floor to a pitot tip.
No Muss No Fuss. Could we also say Good To The Last Drop ?

_________________
Scott Emery
EAA Chapter 326
T-18 N18TE

Scott,
if you install a tank below the level of the main tank be careful of fuel from the main tank traveling to your aux tank. Until the fuel is well below the point in the main tank where the aux fuel is introduced it will flow backwards. I have had this issue on two A/C I have owned (a Chief & a Thorp). Using a inline valve or check will solve the issue.
Phil
118BC

Phil has a good point. Spanky has an 8 gallon aux tank bolted to the under side of his turtle deck. We found that a full main will back fill that aux on the ground.
Cubes

Cubes and All;
I'm wondering if the turtle-deck fuel tank can gravity feed the engine during (reasonable) level cruise flight?
That alone would have merit on a gravity feed ship.

_________________
Scott Emery
EAA Chapter 326
T-18 N18TE

Yes it can. It's been ops tested in my airplane (see Cubes' earlier post). The worst part of my tank set-up is that the filler cap is in the cockpit behind the passenger seat. That makes it difficult to get a fuel nozzle inside to fill up the tank. The last thing I want is a fuel spill in the cockpit.


SPANKY

I would be interested in seeing fabrication and installation drawings, particularly how its secured to the turtle deck. I have often thought of putting extra fuel on the baggage area floor but that that would require a pump, whereas your turtle deck tank does not.

I think the turtle-deck tank could be plumbed with an external filler neck just below the canopy without losing much capacity. A vented cap may leak when the tail came up for flight. The tank could possisbly be lowered a little bit but that may affect the gravity feed option. I would want a way to check the tank for water before flight which means a sump somewhere. Routing the fuel lines downhill for gravity feed could be a challenge.

_________________
Thorp T18
O-320-B3B (160 HP)
68x74 Sterba Propeller

"The joke in aviation is, 'If you want to make a million, you'd better start with £10m.' " -Bruce Dickinson

I think Spanky is going to take some pictures. If there is enough interest, I'll. Have some made. The easiest way to fill it is to measure how much you put in.
Cubes