Author Topic: Fuel Tank Capacity (Read 979 times)

Lee Thiel · « **on:** October 06, 2009, 06:03:02 PM »

Getting to the point that I need to build a fuel tank for the Airabonita. Anyone have an idea as to how many ounces could, should, would be needed for A TT36 for complete flight?
Thanks for any help.
Lee TGD

david smith · « **Reply #1 on:** October 06, 2009, 06:44:58 PM »

Hanging or no hanging? That is the question!! If not then 3-4oz would probably be enough. If you are hanging then obviously you would need more. Then it just depends on how long you think your low speed will be. I flew a friends profile this weekend with a 4 oz tank on it and a Fox 36 and I ran out of fuel at 2.5 min on lap 5. My skyray on the other hand usually does a 1.5 low I think, with no hanging, it has an OS 32 and a 4 oz tank and I have flown almost 3 complete flights on 1 tank. Hope this helps.

David

Lee Thiel · « **Reply #2 on:** October 06, 2009, 07:47:30 PM »

Thanks David, This is being built Class 1. Not a hanger. Have no idea how slow or fast it will go yet of course. Just was searching for some idea. Tank will be buried deep in the fuselage, and I was hoping to get it right the first time. Fast and slow laps, hopefully not more than 3 attempts to land. Its only been about 40 years since I have done carrier.
Lee TGD

Wayne J. Buran · « **Reply #3 on:** October 07, 2009, 04:24:39 AM »

Lee, I sure would have a minimum of 5 oz. That would give you some room based on my experience. 6 0z might be better but you would probably spend to much time draining it.
How about some pictures of the "Airbonita"
Wayne

Balsa Butcher · « **Reply #4 on:** October 07, 2009, 07:54:17 AM »

I would go with as big as a tank that you can get in the fuselage. The Airabonita is a small model though so that probably won't be much more than three ounces if built per plans. A larger tank might be do-able if you moved the F-1 bulkhead forward. The engine compartment is big enough for a rear rotor engine so the TT 36 will give you plenty of room there.
The good news is that if built per plans it will be old school flight profile, drop the flaps and hook and hopefully find a low speed groove between 20 and 30 mph. With that sort of performance in mind 3 ounces should be more than enough. I don't remember how big a tank was in mine, due to the keel, former, and planking fuselage construction, once installed it's pretty much in to stay. Good luck with the Rube Goldberg hook/flap release mechanism. It does work well though.

john e. holliday · « **Reply #5 on:** October 07, 2009, 09:17:53 AM »

Also if the tank is sticking thru the side of the fuselage, don't worry. Several MO-1's were protested one year at the NATS because of the fuel tank not being completely enclosed. Protest should have been made the first year the planes were flown not the second year. Needless to say the protest was thrown out and contestants got their awards. Remember anything protruding thru the surface of the fuselage has to have a max of 1/4 inch clearance. This is on scale fuselages in Class I & II. DOC Holliday

Balsa Butcher · « **Reply #6 on:** October 07, 2009, 10:14:55 AM »

Just my opinion but while a protruding tank might work with the boxy MO-1 it would destroy the sleek lines, looks, and essence of the Airabonita. Better to custom make a narrow long tank and keep the fuselage intact.

Lee Thiel · « **Reply #7 on:** October 07, 2009, 12:36:05 PM »

Thanks for the responces. I suppose I will be building a tank. The plans show the top of the tank to be even with the center line of the engine. Safely, how much could I increase the tank height? Even given some thought to another small tank just behind former B. If pressure feeds it, would it not supply both fuel and pressure to the rear main tank? This would of course be using the main to feed the engine.

I will post some building pictures as soon as I get something worth while. Right now I am at a dead stop because of tank. Working on the wing also and should start assembly on it tonight
Thanks Lee
TGD
PS for Bob R. Looks like I have an excuse to get that super duper metal bender now

Wayne J. Buran · « **Reply #8 on:** October 07, 2009, 03:01:03 PM »

I have Airbonita plan coming so I'll take a look but If it's Class 1 it will be on pressure feed so you can do some engineering for a tank. A formula for capacity calculation probably wont help because the design will be real freestyle. Rabe had some real differant looking tanks in his stunters so its doabl. You might look at those threads for ideas.
Wayne

Balsa Butcher · « **Reply #9 on:** October 07, 2009, 04:12:27 PM »

My Airabonita (still in existence but not flyable) had an internal Veco tank w/a pressure valve. Yup, they made them that way. It allowed the use of crankcase pressure on the K&B 40 RR that it had in it. Since you are going to use the TT36 an easy way to find out how much fuel you need would be to bench run it and see how long it will go on say, 3 or 4 ounces.

IMHO a competition run probably wouldn't need more than 4 minutes of run time (assuming no high power prop hanging). A custom tank could be fabricated but I still would look into the KISS method of fitting a Brodak or GRW 3 or 4 ounce slim line uniflow into the plane. A tubes forward design would allow you to incorporate muffler pressure which I hear the TT 36 likes.

skyshark58 · « **Reply #10 on:** October 07, 2009, 07:15:41 PM »

The plans show a tank and if you get Tom Wilks Carrier CD the magizine article is there with the plans. The CD is a very good deal, a ton of information on almost every Carrier plan ever published + over a hundred 3 views.

Lee Thiel · « **Reply #11 on:** October 07, 2009, 07:59:29 PM »

I have the article, and the plans from the magazine and it shows only a 2 ounce tank. If I build one that is 1.375H x 1.75w x 3.5L that should give a bit over 4.5 ounces. I was concerned about added tail weight by makeing the tank longer. I will run the engine again and see how long it will run on different amounts of fuel. Whats the average time for a class 1 flight?
Thanks for your help.
Lee TGD

skyshark58 · « **Reply #12 on:** October 07, 2009, 08:17:42 PM »

High speed should be about 20 sec and low speed with that airframe with no slider would be doing very well to get 80 to 90 sec. Total flight time with slow down and approach not more than 3 minutes. That's my best guess but opinions are like noses,everyone has one !

Lee Thiel · « **Reply #13 on:** October 07, 2009, 08:59:01 PM »

Thanks Mike, I think I have my tank figured out now at 4.3 ounces. Shape was the big thing, so as not to get tail heavy. Hoping that the top of the tank being .5 inch higher than the center of engine doesn't cause a problem. That part should burn off fast just being a little over an ounce. Weather here is suppose to be really wet tomorrow, so test runs are off till later.
Lee TGD

Peter Mazur · « **Reply #14 on:** October 07, 2009, 09:19:32 PM »

I flew an Airabonita for a few years in Class 1 with an HP.40RR. High speed was about 108mph. Low times were in the 60's; I believe 80 seconds wasn't even a dream. My fuel was 70-20-10, so I used maximum amounts of fuel. The tank was stock. I never ran out of gas.
Pete

Lee Thiel · « **Reply #15 on:** October 11, 2009, 01:37:00 PM »

Did a little fuel consumption test this morning on the TT36. I put in 4 ounces of fuel in the test stand tank. When the engine started, I ran it full throttle for one minute, then idled it down to about 3000rpm or a bit under and let it run. It finally died on its own after 6.44 minutes. It had used only 1 1/2 ounces of fuel. I guess, much to my surprise, the 2 ounce tank will suffice.
Lee TGD

Author Topic: Fuel Tank Capacity (Read 979 times)

Lee Thiel

Fuel Tank Capacity

david smith

Re: Fuel Tank Capacity

Lee Thiel

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Wayne J. Buran

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Balsa Butcher

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john e. holliday

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Balsa Butcher

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Lee Thiel

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Wayne J. Buran

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Balsa Butcher

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skyshark58

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Lee Thiel

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skyshark58

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Lee Thiel

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Peter Mazur

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Lee Thiel

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