Re: Trans-Atlantic model flight

To me, a gallon of fuel in a plane that size is "a bunch"

None the less, remarkable!

It didn't really have a 'bunch of fuel', only about 1 gallon (something like

5 pounds they said) -- which is amazing when you consider one gallon of ANYTHING can contain enough energy to cross the Atlantic.

How many calories per mile is that? I wonder how many calories a tuna needs to cross the atlantic?.

The amazing factor to me is that about 50% of the model's launch weight was fuel. I believe I saw that it had about 2.5kg of fuel, and was burning about

1.2cc/min or so. Add to that the avionics, motor weight etc., and you come up with a very, very light airframe that withstood a transtlantic flight. Amazing. Mind you I wonder if the others broke up or just got tossed around in nasty conditions, or?

Mike D

Thanks for the info Marty.

Indeed a first ranking achievement. When I saw Coleman fuel in some other post, I did not believe it. To this end, you need a high efficiency, which in turn only is achieved at high compression ratios. Coleman (lamp) fuel certainly would not qualify because of it's low octane rating, but high octane aircraft fuel would do I think.

Coleman fuel "IS" white gas.

You're welcome. I've read everything I can at

I may have made a mistake calling it "white gas." I honestly don't know and the web site doesn't say. Carl Layden says Maynard used Coleman, and he seems to have been involved, at least as an interested bystander:

"July 31, 2002 ? Carl Layden

Some of you may ask, "What's FAI legal?"

In this case, it's a model limited to 5Kg, a wingspan & length not exceeding 2M, and an engine displacement of 10cc. Imagine using those criteria to design a model to cross the Atlantic Ocean! WOW!

Maynard Hill and his team from STAR (Society of Technical Aeromodel Research) have done just that. The model is not unlike most of the models we fly. It is built of balsa with Monokote covering and is powered by an OS .65 4S. It weighs approximately 5 1/2 lbs dry and it holds 5 1/2 lbs of fuel (that's a little less than 1 gallon). The fuel is Coleman fuel, white gas - yes - the same stuff you can by at Wal-Mart or Canadian Tire."

Coleman fuel seems to be a naptha, while white gas is unleaded gas without any other additives.

"Although Coleman fuel and other camp fuels are routinely called white gas, they are actually a naphtha. The two are very similar in characteristics. Naphtha is refined one more step and is therefore considered cleaner. It also has a slightly lower boiling point than unleaded gasoline, although it is in practicality undetectable. Coleman fuel has some additives to help prevent rusting of internal parts and facilitate long shelf life.

"I feel confident in recommending it for other brands of stoves that burn "white gas," but it would be prudent to check with the stove manufacturer.

"Jim Reid --- Coleman, Director of Public Relations "

Marty

Coleman was the pilot. It was part of his bid to become governor of CA.

I can't believe it. A second guesser.

I would bet that Maynard has experimented and found that Coleman fuel is the best compromise, for what he needed to do.

When you make a model fly 39 hours, then you can come back with your theories, and I won't laugh at you.

Ta-ta Jim in NC

The web site glosses over the fuel mix & CR details.

We'll just have to wait for the coverage in the magazines to get more info, I guess.

Maynard says he's been thinking about this for 20 years and developing the TAM series for five years. It would be interesting to hear how he arrived at his fuel/lube choices.

Maybe if they go the 120 octane fuel, they can do NY to Paris next. :o)

Marty

Several points to consider. High compression ratios require heavy engine cases and the O.S. 61FS is NOT one of those. Second, the oil mix he used probably helped raise the CR from 6. The oils I know have been tested are NOT your standard run of the mill 2 stroke gasoline oils.

In the SF Bay area there was a guy running gasoline in a O.S 61FS in the mid to late 1980's and he found the need to use a Veco .19 carb or there was gas everywhere.

You seem to prefer the value of non-documented rumour over hard-earned general knowledge and lessons learnt. I advise you to read the work of Ricardo, which he wrote as early as 1922. There is no excuse for ignorance if you do not take the trouble to enlighten yourself. So to give you the advantage of doubt: Maybe you have information that we don't and want to share with us?? i.e. a special anti-knock additive? Or fuel injection used? The porpoising problem they experienced in this flight, and lean aborted flights in the past, point in the direction of normal carburetion though.

Dunno.

The fellow who posted in this group said they were using a small carb. I misremember the size. Makes sense when you're only burning 2.2 oz per hour.

Hmm. That gives a clue about the size of the fuel tank. I think the goal was a 40-hour engine run, which would work out to 88 oz. or so.

Marty

Marty, Geoff,

I am realy interested in this Coleman thing, so I did a Google search and found the octane rating yo be 53. The search rated coleman from 6!! to 87 This is what

states:

Quote: Most engine owners are using Coleman Camp fuel with good results. My Plunket Jr. engine has higher compression than most model engines and I noticed that it made some strange knocking sounds that were not mechanical, so I decided it must be detonation. Wondering what the octane rating is, a friend called Coleman and was informed that the octane rating is only 53. No wonder that it knocks! Knowing that methanol (used in may race cars) has a very high octane rating and burns clean, I went looking for a source and found it at an automotive speed shop. My Plunket Jr. and PowerHouse engines love running on alcohol! Valves and plugs stay clean, and there is no more knocking, but cold starting can be somewhat difficult. Unquote

Te use of Coleman seems doable, but imho hardly likely by the abundance of much better fuels. I hope the Maynard group will shed some light on this. I am sure they chose the best fuel available to them.

My curiosity getting the better of me, In boating engines I found

They experienced that a blend of 25% coleman improved torque. Quote: We tried white gas mixes with all lots of different fuels to slow the burn front in the combustion chamber( works like a jewl in VW and some small bore italian motors) this allows more ignition timing to be used and usually increases throttle response and some times hp it almost always improves torque. Octane rating alone is not what should be used for fuel choice . WE could fatter up the torque curves with up to 25% coleman fluid but it fell off fast after that. " mmmm...

Thanks for the info, Pé!

Yes, I hope the coverage deals with the fuel development.

Maynard's mix may serve a number of different purposes, endurance (or efficiency) just being one of the factors he considered. But this is a totally amateur guess (TAG).

Only Maynard knows for sure. :o)

Marty

While I am not informed of all the details...I was told a story by the team when they were here.....Maynard was doing his usual testing of the fuel and he made a call to another member to ask him to find out if Colman had made some changes to their fuel. He was apparently getting some different readings with engine performance. After a call to Colman they found out that Colman indeed had made some very minor changes in the chemical make-up of the fuel that was not supposed to be noticed by the end user......I guess Maynard was not your typical end user.

Craig

One of the most important things when choosing Coleman fuel over alcohol, is the fact that gasoline has 2 to 3 times energy content than gasoline. The model would have had to carry more than twice the amount of fuel! Not possible!