Thorp Air Command - T18.net

I think you guys are making assumptions about the W&B concerns regarding the larger tank, ask Dave I believe the change in CG from the standard to 40 gallon tank were minimal at best. The more invasive concerns regarding the larger tank are the modifications necessary to the structure to accommodate the tank itself (it's not a turn key install).

Also if you guys are ok spinning an old tree branch out in front that's great, I prefer to fly through rain, out climb/cruise and swing a big fat paddle out in front!

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Lee Walton
Houston, TX
N51863,N118LW
KEFD

40 gallons instead of 29 moves the CG forward .6 inches (disregarding the weight change of the tank). On my airplane with a 180 and constant speed prop, this is still well within the allowable forward CG. The next thing to consider is the effect on gross weight. This should not present a problem unless you plan do aerobatics with full fuel. In this case, you will probably exceed 1250# @ 6G's pretty quickly.

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Bob Highley
N711SH
SN 835
KLAL

A turn key install it would not be , but the benefit of a single tank and the required mods to support the tank would out weigh the wing tank installation , especially on an S-18 . IMHO . Even a 5 gallon increase in the larger tank would be useful . Bada Bing, Bada Boom !

RB

The 5 gal increase would not be hard to do.....Dan

Bob is correct, the cg is not a problem. I calculated first and it is well within limits, then flew with 40 gal fuel, only me, and nothing else in plane. No ill effects with my 0320 and a wood prop. Even with a lightweight pilot it should be fine. I did beef up all of the associated supporting structures tho.

I think the increase in fuel capacity is a great thing.....having said that (and this is just lightweight little 'ol me), I have not once in the 7 years of flying 2 T-18s to infinity and beyond, (means Ontariairyairyoh to TX and points west) ever had a situation where I had to be concerned about fuel - my bladder runneth over before the fuel runneth out - every time....I don't plan fuel stops - I plan drainage breaks.....having/having said/said that/that, if I were to dabble in the secret sordid world of IFR, more fuel would be a more serious consideration.

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Fraser MacPhee
N926WM
Serial #279-1
Angel Fire, NM (KAXX)

I made a quick exercice.
I strapped the fuel tank on a fork lift.
After I fill my tank with water and finally I drained the water to calculate the internal tank capacity.


My tank hold only 23 US gallons.
Minimum I need is the original 29 US gallons on my T-18.

I have to find the easy way to increase the volume to minimum the standard fuel tank!
I put all your ideas in my hat and I pick-up the best!

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Thierry
French Canadian T-18
C-FPVE #091

I my opinion you can NEVER have too much gas ,even VFR ! (unless you were at the OSH house! You have NEVER smelled such foul toilet gas !) 2-2.5 hours is my bladder full lite ! David's tank would be a nice option to have .
RB

I have considered enlarging my fuel Tank, I agree with all that has been said in regards to this a little extra fuel is good to have. I will typically run 25 gal in the tank and call it full, a 2hr / 2hr -20min leg will burn 15 gal out of the thang and at that point like Frase says my bladder will embarrass me if I don't get on the ground and emtey it out. I can stay aloft for almost 3 hrs safely and have some in the tank when I come down, but Ive never made the 3 hr leg without reaching for the relief bottle, so I just plan for about 2hrs and a little bit for each leg. seems my bladder is shrinking with this thing we call age..........Dan

I carry 62 gallons, 33 in the wings and God has seen to it that I can fly from LAL to CKB in 4.5 hours non stop. Wing fuel has no penality in flight. Rich is correct the only time you have too much fuel on board is when you are on fire. I have flown non stop from Kentucky dam to Lakeland on top and without that fuel could not have made the flight. The Thorp with the big motors need 3 hours of fuel plus reserve.

Can you cut the end caps out and turn them around and weld them back in? Like they should be.

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http://www.dixiefriedfabrication.com/

I think Lou has the faster solution!!!
Cut both end and make new side.
My plan B solution is to keep my tank and install Tom Hunter external fuel tank.
My tank 23 gallons + external tank 10 gallons = 33 gallons total.
I have to sleep on this possible solution!

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Thierry
French Canadian T-18
C-FPVE #091

Hi Thierry, We should talk. I have a spare fuel tank with my 2 projects. The big issue is going to be getting it from Florida to Canada.
It's a standard 29 gallon tank. Unused, Unmounted with bungs for the fuel sender and finger strainer.

Terry A. Hagle
Destin, Florida
850-974-5608 cell

Bill : You must have flown F-4's ! "On Fire and out of Gas! "

RB

I do not recommend external wing tanks. Anyone who has flown a fighter can attest to the destabilizing effects of external tanks. By the way, if you have wet wings, please have a way to ensure they are empty before any high load or angle of attack work is done.
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