Author Topic: 30 cc Hanger 9 Spitfire  (Read 4931 times)

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Offline Paul Lange

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Re: 30 cc Hanger 9 Spitfire
« Reply #15 on: February 09, 2017, 08:07:51 pm »
Congrats on the Hanger 9 Spitty Maiden today.......let the hanger "tweekin" begin!!

I found out how nice the FMS 1500mm P-47 Razorback can fly in calm winds this evening......marvelous.....I have another all day touch-n-go bird.

All fun

Paul H Lange
Best Regards - Paul H Lange

Offline dlabby

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Re: 30 cc Hanger 9 Spitfire
« Reply #16 on: April 25, 2017, 02:17:50 pm »
I failed to update my Spit problems. Got 6 short flight on her with 3 or 4 dead sticks due to engine overheating. Several iterations of improvements thus far have been unsuccessful. I would not recommend this plane/engine combination. A guy in El Paso has exact same problem. Last set of improvements did not help on driveway engine run but it is ready for another 'cowl on' test flight. I will fly 2 minutes, land, check temp. Hopefully, cooling will be better in flight.
Darrell Abby

Offline Herb Koven

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Re: 30 cc Hanger 9 Spitfire
« Reply #17 on: April 26, 2017, 12:23:51 am »
In theory, increasing the percentage of oil in your fuel should decrease cylinder head temperature. The oil in our fuels perform 2 functions, lubrication and cooling. Since the oil is not burnt during combustion a portion of ignition heat is carried out of the exhaust. More oil more heat extracted.

Easy test, run 2 mixtures of fuel with different oil content on the driveway and measure cylinder head temp and prop speed.

Remember, this recommendation is from a guy who has never flown a gas ignition engine.

Herb

Offline Lane C.

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Re: 30 cc Hanger 9 Spitfire
« Reply #18 on: April 26, 2017, 09:38:09 am »
I feel Herb has a good point. A good ratio is 32:1. Easy to remember too. 4 ounces per gallon of gas. Spits some oil on the aircraft, but easy to clean off. You need to keep a check on plugs as they tend to foul out quicker, but changing plugs is an easy thing, you won't need to do this every few flights - they can stay clean much longer than that. Usually the engine will tell you when to check the plugs - inconsistent idle is one sign.

A DLE-55 is plenty of power for the H9 Spitfire, so no need to try to squeeze out the most power using less oil in the mix. Also, try changing out the prop to less diameter or less pitch.

Offline Herb Koven

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Re: 30 cc Hanger 9 Spitfire
« Reply #19 on: April 26, 2017, 04:40:46 pm »
Since the prop is the pump that produces the airflow to cool the engine, going to a smaller diameter and increased pitch will increase the airflow into the cowl. The total prop airflow might be reduced but your concern is about airflow around the cooling fins. In this case, more is better.

Herb

Offline dlabby

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Re: 30 cc Hanger 9 Spitfire
« Reply #20 on: April 26, 2017, 07:48:35 pm »
One of my changes was going to 30:1 mixture. (More oil than I run in the 55's. ) Forgot to mention that. Prop is something I can try...if the wind would drop off a little.  Running 18x10 right now. Thanks.
Darrell Abby

Offline Lane C.

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Re: 30 cc Hanger 9 Spitfire
« Reply #21 on: April 26, 2017, 10:55:10 pm »
Darrell, forgot you are running a DLE-35, not 55. I run a Xoar 19x8 on my DLE-30 on both the 74 inch Corsair and 1/4 scale J-3 Cub. Seems the same prop would work well on the DLE-35.