MTK

OUCH!!! A wet rag done right makes a hell of a weapon...it is called a whip!

Tseres

Nah! Don't Hurt Him!!! I'm afraid it might delay the release of the 38.

Michel

Hi

Well,.......................... The first 28cc JC engine is broken in . It,s not hard to tell , the dam thing has so much power , it really is surprising a lot of members . We have been useing an 18 X 6 Xoar in a 28cc trainer , and the engine is running great , a very prod owner . Now ,............ it,s time to change the prop .

Whats the best choice :
1 ) 18 X 8

2 ) 19 X 6

3 ) 19 X 8

4 ) 17 X 8

Somethoughts would really be appriciated .

Thanks for looking

Michel

y2kcbr929rr

My Feedback: (2)

who makes a 19x6 ? I am currently using a MAH 18x8 Carbon that i bought a few years ago at the WRAM show.....

y2kcbr929rr

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Is anyone running high octane fuel? if so how does the engine like the difference?

Michel

Hi

Is there anything else

Michel

Michel

Hi

Have no idea who makes a 19 X 6 , but how does youre engine work with a 18 X 8

Michel

Whaleflyer

My Feedback: (6)

Xoar makes them, Jodi stocks them ....

http://www.valleyviewrc.com/Xoar%20Propellers.htm

RedwingRC

Hey Guys-

I have some 19x6's in the Hawk Props.
http://www.redwingrc.com/accessories.html

apalsson

My Feedback: (1)

Xoar, Hawk, JXF and many others make 19x6
Henry sells Xoar props
http://www.rcaer.com/store/Results.cfm?category=9

Michel

Hi

What I would like to know is what is the better matched prop for the JC-28 . I need to know that before I buy a prop . It just kind of makes sense to know WHAT one wants first .

Do you know witch one ?

Michel

Champ-RCU

My Feedback: (132)

Michel,

Are you keeping the engine on the trainer? If not, what plane?

I have a Bolly Carbon Fiber 17X10 on mine pulling around an Obsession 3D and it's almost a perfect match. I originally had a Zinger 18X6 ( I know paint stick.) on the 28/ Obsession combo and performance was disappointing. Bolted the Bolly on and instantly it was a fire breathing monster. I don't do 3D, however I can do 1/2 of a large loop and at the top roll upright and do another large 1/2 loop with no problem. Down line breaking is not as good as with the Zinger. With the Zinger, it seemed like I needed to add throttle to bring it down. Of course the Obsession has the wing loading of a glider.

Love my JC 28.

Mark

y2kcbr929rr

My Feedback: (2)

Michel
What fuel are you running? manufacture and octane level? and the 18x8 pulls a 13lb sig rascal 110 with ease only full throttle is strait up..........

Michel

Hi

I,m running a high octane level , with Red Line oil at 40:1 . The plane is a trainer and it weights 18 LBS ( I imagine ) It,s on the heavy side .

Michel

Tseres

Hi Michel

I used a 17-8 Xoar that I got from Henry on the Cub. Needed ground clearance and couldn't use bigger .Cub weighed 13+lb. Used 3/4 throttle for vertical and had to let off to do a hammerhead or it would get to small to see for an old man.

MTK

Why are you using high octane gasoline? Is there some reason to do so, such as high compression, tendency to detonate or vapor locking?

High octane doesn't mean higher power....it simply means that the gasoline will vaporize slower and burn slower. Do these engines need it?

G.Barber

My Feedback: (1)

I also have a JC 28. I run the 87 octane, and the 28 is in its second plane. I have flown it in a Wings Maker 1/4 scale Super Cub- way more power than needed, and it is now in an Aeroworks Cessna 195- again, way more power than needed! I am amazed at the output of this engine!

MTK

I prefer using high octane gas such as Avgas 100LL. It's 5$ per gallon but worth it if it works. This type of gas has no alcohol in it and smells super...it delivers more energy density because no alcohol. Also, stability long term is far greater than pump auto gas. So you may mix a 5 gallon can and it will still be good 6 months later. Can't say that about pump auto gas

I used it in a different gassie (SAP180) and that engine is not set-up to take advantage of 100LL. Symptoms were fat mid range and fat at full throttle.... that's how much the burn slowed down.

If the YDA and JC engines are capable of taking advantgae of Avgas 100LL, that's an important variable to me

thanks

aussiesteve

I use high octane pump gas (NOT 100LL or any other avgas) in all my engines.
I don't use it for higher power, I use it because it is better refined and cleaner burning than the "Regular" gas is. I do however have one very high compression engine that does need it and I am also lazy about keeping 2 fuel mixes (but that is a minor reason)

High octane automotive Pump Gas does not burn slower than regular pump gas but Avgas does burn slower than automotive gas as it is designed for slower revving engines. (which is why I don't use 100LL). Yes the vaporisation is correct but it is not enough to worry our engines.

Most people run these engines very happily on Regular pump gas - no issues there.


Matt - in your next post - you described the effects of a slow burning fuel. Many think that high octane numbers are the be all and end al measurement - it is only part of the story. You wil find the fatty running is a symptom of a slow buring fuel in a high revving engine - thus needing a "rich mixture" to get adequate burn to produce the power the engine can give.

Try it with high octane auto gas - for exactly the same reasons you mentioned - you may find it makes a difference on the 180 (compared to the 100LL) - all the other reasons remain - longer shelf life etc..

Super08

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Steve what did you guys do with Henry? We are starting to think you guys are going to keep him over there.

aussiesteve

Oh - it gets real bad from here.
In the next couple of days he will be visiting Ari - that can only be leading to a hangover and a half.

I also have it on very good authority that Kath will cut out his "manly bits" if he spends any more time on his computer than is absolutley necessary.

He has some pretty good stuff for you all when he is brave enough to get back on line

I am worried he will stay too - I can only have so much alcohol displacing the 40:1 redline from my own veins.

Super08

My Feedback: (2)

LMAO!!

MTK

Are you saying the YDA engine line may use Avgas 100LL? Or should they only use pump gas (87 to 93 octane number)?

I want to get away from the stink of pump gas.

Many years ago I worked as a Chemical Engineer in refining and formulating these materials.... I no longer have access to the lab

y2kcbr929rr

My Feedback: (2)

I have been using 103 octane unleaded race fuel 1:1 mix with coleman white gas "camp fuel" and it gets me about a 93 octane rating no "pump gas smell" and runs great and 32:1 redline oil i still have the needle settings as per in the manual for the JC 28 and it runs great...........

Q500RC

it sounded to me like Steve was saying in the above post AV Gas burns slower than auto fuel and he was
recomending the use of auto fuel not AV Gas!