j lauria

Tom
I just sent pictures to your Email
J

Maxam

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Got em! I noticed his collector ring is inside the engine accessory cowling. -Tom

badangle

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siskn, im courious, who makes a 89" stearman? im putting my 7-77 in a ziroli 77" stearman.

slskn

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badangle my Stearman is the flair kit, it is supposed to be true 1/4 scale I have pics on previous posts not sure which ones but is the all yellow with the blue tail rudder, I bought it from another Modeler who built it but it has not flown as of yet He had a gas banger G-62 Zenoa but I purchased it with out the engine but, I plan on putting the 7-77 0n it.

Pete Bergstrom

Hi!

 

I have been following the thread on RCU and I have the following thoughts.

 

Using some of the scale drawings I have available to me here I have the following numbers for you to consider for the proper scale look:

 

Wingspan                Cowl Dia     Eng Dia      Prop Diameter

77"                     9.16"       8.7"              20.5"

87"                     10.35"      9.9"              23.0"

 

The diameter of the 77cc is 9.1".  The diameter of the 99cc is 10.2".

From a scale appearance point of view I think the 77cc would be perfect for the 77" airplane and the 99cc would be perfect for the 87" airplane.

 

The power of the 77cc is equivalent to a good 50-55cc single cylinder engine for the reasons that Maxam explained and would be more than enough for either of these two airplanes.

 

A 20 x 14 prop used on the 77cc in the 77" airplane will give you approximately 22lbs of static thrust and 23-24 pounds in the air.  For a

30 pound airplane this is plenty of power.

 

If it were me I would move forward with your original plans for them 77"

airplane with the 77cc engine.

 

Yes - the 99cc engine has a collector ring available for it.  The part number is: EVO999114.

 

Thanks for including me in your discussion.  

 

Pete

booker-RCU

My Feedback: (43)

Hi all - It's been a while since I've posted here but I wanted to let anyone who is interested that I finally flew my Waco with the 7-77 in it.
It was an excellent flight and all went well. The engine ran great and sounded even better than great.
This is truly a fantastic engine.

Galen

Maxam

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Galen, I was wondering about that plane. Looks really great and must be a perfect combination. Darn it, now I want one! -Tom

badangle

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bookerglad to hear of your success....if you remember I was thinking of getting same plane but went with ziroli stearman...but now I have to build it.can you tell me what the weight is and what kind of performance the 7-77 delivered?

badangle

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pete

thanks for the info. the 77 inch kit says weight is 16-20 lb.....87 inch says 30-34 lbs......is this the plane only weight or is it meant to be ready to fly weight?    spoke to someone at ziroli who thougth  7-77 was too big for 77 inch plane.... 

if the 7-77 will fly the 87 inch stearman the prop clearance issue is solved...

I admit the 7-77 looks a bit small on the 87 inch plane but now I wonder if ill have balance issues in the 77 inch ....cant find weight of quadra 40

engine plane was designed for...might help if I knew what engine the 87 inch plane was designed for..but I don't have plans for 87 inch

GUESS I JUST WORRY TOO MUCH....its too late anyway,i purchased the 77 inch kit...

j lauria

Badangle,

I don't think that you are going to have a problem. I have plans for both the 77 and 87. If you use a 20X14 prop you should have enough ground clearance. I have communicated with Pete Bergstrom, from Hoizon Hobby who thinks that the 7-77 should be perfect for the 77 inch Stearman and the 9-99 just right for the 87 inch. I have gone with the 87 inch with the 9-99. I have a National Balsa kit for the 87. Plywood former FS1 is cut 3/16 to short on one side. ditto for FS2. I can't explain how I decided on the 87.
John

badangle

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j lauria

right thrust and down thrust built into FD1 and FD2...mine are long compared  to plan.

booker-RCU

My Feedback: (43)

badangle - I can't give you an exact weight as the wings are off for transporting to the field. I'm guessing around 24 lbs. but I'll weigh it when I go to fly it again.
The 7-77 had way more power than was needed to fly it scale. It ran just excellent - never missed a beat. When I was taxing out I let the idle get to low and the engine quit. It took only one flip of the prop to get it going again. A truly impressive engine.

badangle

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booker

I cant wait to get mine running....your Waco looks fantastic...did you beef up any structure to handle engine weight?

booker-RCU

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I didn't make any mods to the firewall or anything else for that matter. I did use hardwood for the engine mounts rather than metal standoffs. To get the CG I moved the two batteries ,a 5000 mah NiCad for the glow system & a 2200mah A123 for the receiver, back equal to the trailing edge of the bottom wing. I came out just right. The only fault I could find with the aircraft was the push rod ends were not glued securely into the carbon pushrods. Also the striping on the cowl did not match up with the striping of the fuse., so I ordered a new one and it fit fine.

Tom in Cincy

My Feedback: (16)

Will the evolution wiring harness fit on OS F plugs wider center post? I was going to use the caps on my Saito if its a good fit...

pappy 883

My Feedback: (2)

I'm using the OS F type plugs on my 7-77 and the harness works fine. One of the crimps was bad, but other than that it's a good unit .

EQ1

Hello!As promised I would like to give a feedback about the unusual noise in my EVO 9-99. I talked to a support guy at Horizon in Germany and he said they are not servicing the engines themself, but have a company in Hamburg doing this. Furthermore I was told that this noise, as described in my previous post, every eighth revolution, is not uncommon. They have several engines doing this and they work OK without any loss of power. I should use it as it is. Therefore I built a test stand and let the engine run: sounds OK to me. Video is here: http://www.youtube.com/watch?v=CNktS14E7Fo
The only thing that bothers me is the color of the oil coming out of the engine (fuel with15% oil). It is grey, indicating metal parts from abrasion. Well, it is not unusual to have some abrasion during breaking-in, but for me with a long experience in model engines and being engineer by profession this seems to be more than expected. After three runs and around 4 oz fuel (varying rpm) the noise is a little less than before. I suspect I have to go with it as it is and hope the best. At least I have two years of waranty in case.

Have a nice day.

Olaf

SWORDSN

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Those running the engine cowled .Do you remove the cowl after each day of flying for the maintenance,adding after-run oil,draining cylinders etc. ?Seems that it would be a must.

Nelson

Maxam

My Feedback: (62)

Nelson, My corsair is tightly cowled and I do not need to remove it to service. Firstly the rockers keep themselves well oiled from the engine. Now to drain the front case just make sure the valve you want to remove the pushrod and and follower from is not on a cam. Just push down on the pushrod to disengage it from the follower and remove the follower. Easy to reinstall too. -Tom

movonzez

Hi Gents! I have a question about your experiences with the carburetor stetting on the 777: mine is actually used with 8,5 % Aerosynth 3 Oil, 5 % Nitro, the rest methanol. As glowdriver I use a Microsens Glow7, all mounted in a SU26. The problem I have is, that I'm not able to stabilize a reliable, low-rev idle. When I start the (warm) engine and adjust the throttle to a acceptable setting the engine idles not perfect, but as low, that the aircraft doesn't move from the residual thrust. Then, when opening the throttle, the engine accepts the mixture perfect and runs up. When I now close the throttle again to idle, the engine run down an stops after some revs. When I play a little with the throttle short before it dies, the idle stabilises and the engine doesn't stop. This behavior is not really acceptable, because the residual thrust is larger than is has to be. I also use a 735 in an AT6 Harvard with the same fuel and glow settings and it idles at about 1.000 - 1.100 revs absolutely reliable. The 777 I have to operate i idle at about 1.800 - 2.000 for not letting it starve. Both engines have about 3 - 4 hours of operation counted. I have no idea how to set up the carburetor or anything else in another way to generate a reliable, low-rev idle, especially during throttle changes from max to min. Did you make comparable experiences? Would probably an alternative carburetor (f. e. from the OS FF320) help? Thank you very much!

Maxam

My Feedback: (62)

Movonzez, I did not see your post till now and apologize for not responding. The carb on this model needs to be on the rich side at idle or else the midrange will starve out of fuel. Are you using very large diameter fuel line with a short distance to the tank? At full throttle can you make the engine go rich by opening the needle valve? If not, try adjusting your servo where full throttle is 3/4 open at the carb. The fuel draw is improved with little to no loss of power. Try it! -Tom

Maxam

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For the 9-99 people. You might have seen earlier posts about my concerns with internal corrosion trying to set in. Many times regardless of extensive oiling and draining the engine starts to "crunch up" the next day indicating the onset of corrosion. Last Saturday I flew 8 times and oiled and drained the oil. It was a somewhat humid day. I got home and oiled and drained again and yep, could see water globules in the oil. The next day, sure enough the evil crunch started to set in. Turning the engine over in this condition will release a bad corrosioney smell from the exhaust. I ran the engine that day at home to blow out any corrosion. I thought and thought about what to do about this. This engine has a huge crankcase......water can condense everywhere in this cavity. All the water that condenses cannot be hosed out. Why not ventilate out the crankcase!!! Rid the water by evaporation. I got an aquarium air pump and attached the tubing to one of the lower cam follower guides (cam follower removed!) and ran the pump overnight. The vented air goes out the carb. The next day the engine was silky smooth. Cranking over the exhaust smelled clean with no corrosion oder. The next day still silky smooth with fresh smelling exhaust! This engine has nearly 120 flights on it and my goal is for the engine to last 1000 flights. Right now I feel confident this is possible with the right care. I will report if this treatment is consistent. It certainly is easy. -Tom

j lauria

Hello Maxam,

I have purchased a 9-99 after reading all of your posts. I am starting to build a Ziroli 87 inch Stearman for it. I purchased the Keleo exhaust ring after determining that the UMS ring is placed farther aft of the cylinder heads than the Keleo. The position closer to the heads I believe will allow for mounting the engine at the prescribed distance from F2 on the plans(10.5 inches to the aft face of the prop) and leave about a 1/4 inch of space between the ring and the fiberglass cowl. I hope that this will be enough space to avoid burn marking the cowl. If I had used the UMS ring I would have had to mount the engine farther forward to clear the cowl. Functionally and cosmetically I think that the Keleo ring will be a better fit. Also I think that the Keleo ring, being made in three pieces with half as many nuts to align with the heads, will be easier to install. I expect to receive the ring tomorrow. If all goes well I may be able to post pictures of the engine mounted in the fuse in the next couple of weeks. Does this sound like a reasonable approach?

John

Maxam

My Feedback: (62)

John. The exhaust temp is so low that a 1/4 clearance should be fine. -Tom

j lauria

Tom Many thanks
John