Maxam

My Feedback: (62)

Lars, That is priceless! Merry Christmas to you too and your family. Thanks for those nice pictures. -Tom

CzDavec

Hi, I am new to having a radial but have always wanted one and Santa obliged me with a 7 -77 and a giant corsair to put it in. I have read this forum through and there is a ton of helpful advice here. I will be carefully breaking in the engine on a test stand to become familiar with it before mounting in the plane. One question that I have is fuel consumption rate . My gassers sip fuel but my large glow engines tend to use large quantities.
So what I am looking for is some input as to a proper size fuel tank to provide around 8 to 10 minutes of safe flying time as I have been stranded in the pattern when a problem occurred on the strip and with this fine engine I don't want to push my luck.
Thanks in advance for the input. Great thread by the way !

Dave

cymaz

Manual says about 2 fl oz per minute and it's not far off. It might be a little bit under that. I put a 32 fl oz sullivan tank in my plane. Plenty for a 10 flight and there is always a bit under 1/4 in the tank after the flight.

chorner

so cymaz, with the 24oz tank (in the Hangar 9 60CC Corsair anyhow) we'd probably be on the verge of running out of fuel with a 24oz tank after a 10 minute flight. Hmmm

cymaz

Yep....page 4 in the manual

BobH

My Feedback: (2)

I think the fuel economey is better than that. Judging from my limited experience. That estimate in the Manuel might be bastd on wide open throttle running all the time?
A twenty oz. tank should work and certainly a 24 would be plenty.

Reverend

My Feedback: (3)

Hey guys.

I have a freinds evolution 7-77 here. It has quite some hours on the clock. What is a bit disturbing is the fact, that the engine is very tight on turnover. I seem to remember someone having a simiar problem.

Anyone remember what the cause was before I pull it apart?

Thanks in Advance and happy new year to all!
Rev

Dad_Roman

How long has it been since it last ran?

What formula of fuel ran through it?

Reverend

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it has been about two months. My friend bought it used and the buyer is not reachable. It looks like castor though.

Seems like it gets better when you loosen the Propnut slightly... ?!?

Looks like I wont get around tearing it down...

Maxam

My Feedback: (62)

Flood it with glow fuel, I mean fill it up FULL through the carb and let it sit for a couple of hours. Then drain the fuel out. Now remove all plugs and flush out the cylinders. Now see if it frees up. The nitro and fresh methanol will soften and remove the castor. -Tom

Reverend

My Feedback: (3)

Hi guys,

I tore the engine down completely today and found the culprits. The front bearings were full of castor gunk. Thanks Maxam, your tip would have been perfect. I threw the whole front assembly in my big ultrasonic cleaner, rinsed it and dreid it in the oven. After oiling everything up well I reassembled it and put it in the Airframe. Now the engine roars like I want it to.

https://www.youtube.com/watch?v=xiW4DHRWUT4 The picture is after the cleaning.

Rev

Maxam

My Feedback: (62)

Great! Glad to see a happy engine and owner. -Tom

cymaz

Glad to see the bearings looks nice and rust free.

Dad_Roman

Yep....all is well (castor )

CzDavec

Thanks for the input, That's what I was looking for. This forum and the people on it are what made my decision to buy the radial over a turbine .

Maxam

My Feedback: (62)

Thank you Dave for the kind words. -Tom

Pull Up Now!

My Feedback: (3)

For you gasoline people, I think this might be a worthwhile. If OS can get this engine to run on gasoline with a special glow plug, there's no reason why a radial can't do the same thing. The potential benefits are no rusting of the internal engine parts as with methanol. It's also cheaper, and less messy. The potential downsides are insufficient oil to all moving parts, though I think the risk is minimal. Another possible downside is preignition (pinging). I don't know what the technology is behind this new "glow" plug. Nitro glow plugs have the element coated with platinum, and it catalyzes to keep glowing. (that's why a glow plug can wear out without actually severing the element). I wonder if these gas glow plugs work the same way. But, the big benefit is one doesn't need to purchase an expensive radial ignition module to convert the 7-77. As for the pre-ignition, maybe that is a lower risk on a radial than a single cylinder engine because more time passes (to cool the cylinder wall) between explosions. I surmise maybe a glow driver still being necessary. Here's a link to the OS engine. http://www.osengines.com/engines-air...513/index.html

mogman

I read somewhere, don't remember where, that the gas/glow plug is a different size and thread.

I've been running my 77 on gas and ign for some time on a test stand. I've had a built, but unfinished Giant Aeromaster hanging up in my shop for about 6-7 years.
It now has the 77 on it! I have the plane apart to cover it, but I will take some pictures when I'm finished.

Cheers,
Dave.

Pull Up Now!

My Feedback: (3)

I'll find out what thread it is. Since they say the hex and the contact pin are compatible with current glow drivers, it can't be too far off from 1/4-32.
I tried to scale a photo, but it was taken at an angle throwing the numbers off. But it looks like maybe 1/4-40. I used the 5/16" hex to kind of scale the photo. Very preliminary.

Straightleg

The G5 glowplug has 1/4-32 threads, (checked physically)

/terje

Pull Up Now!

My Feedback: (3)

OK, thanks for the info. Maybe the long protrusion on the 2714 Gas-Glo plug is designed to keep it from being used on anything but the OS gas glo engines.

Straightleg

Could be. It was a friend that checked this out for me, so I do not know if it is too long for the 7-77, but if not and the engine will run on gasoline, that would be a major breakthrough. Anyone in for testing?

/terje

garyFL

If it's too long could a shim be used to correct this? Also, does anyone have a link for a dealer that sells the G5 Glow Plug? I've done a limited search and haven't been able to find one. Only thing I come up with is the OS engine with the plug.

Gary

Straightleg

Here is a link:

http://www.brhobbies.com/products.asp?cat=113

/terje

garyFL

Thank you.

Gary