chorner

Thanks Nick Definitely a tight fit. Glad I at least stuck with the 7-77 for now instead of switching to the FG60/84 myself. It really looks great when mounted. Very unique look, just hope it runs strong and reliably enough!

As far as props go I've got a Mejzlik 22x12, 24x10 and the 22x10 3 blade for now. I will test RPMs with all of them and decide what to go with. See what I get out of the engine before spending money on another 3 blade I'm not really afraid of pushing the engine to its max RPM on the ground, just as long as it's not above the 6,300 mark as I won't fly it WOT for more than a handful of seconds at a time anyhow. So I'll run things through a calculator when I get some rpm numbers. Just looking for a good amount of thrust and enough speed range to keep it in the air comfortably without feeling like I have to pin it in corners. I recall David Payne recommending the 22x12 but that wasn't on CDI... have one to try anyhow!

pic of my throttle linkage. Haven't installed it in its final config as I plan to run the engine on the bench first but this is what it looks like using the "stock" location out in the nose which is great. Didn't want to deal with long runs of push rod and bends inside the fuselage.

Thomas Schultz

PM reply

Ted62

My Feedback: (2)

Has anyone recently done business with Microsens? I have sent $$ and have heard nothing back in several days. I hate using Paypal in the first place and this experience isn't helping. Thanks.....

mirored

My Feedback: (1)

Not sure why messages are not making it. Can you email me at [email protected]

Cpig

Ron,
Have you flown it yet? I'd like to come on down to the Sky Corral if you've got it up and running. I brought my YA Spitfire down for your warbirds event last year and really liked your club, great bunch of guys there. I just got my H9 Corsair and have stripped it and am in the process of glassing and finishing it. Haven't decided on engine yet but leaning towards another EME 60 with electric start; really happy with that setup on my Spitfire.

njmheli

Hi All.

I decided to get the 7-77 out of it's box and finish converting it to run on gas ( whilst I get my head around an idea I have for the Corsair ).......As said before I bought the CDi conversion from Adrian at CH ignitions last year...having seen what "Morris" had done with "Bob's 7-77",thought I would convert it also......

My 7-77 is around 2 years old now and has in excess of approx 5 hours total running on glow fuel ( mix as recommended by Evolution )...........thought that I would take the back off to have a look inside.......to see what corrosion,may have taken hold !!!

I was very pleased to see that all was good in there !!! plenty of oil everywhere and looking pretty new aswell.........massive ball bearing on the crankshaft and a pretty "chunky" one on the crank-pin too !!!!

IT DEFINATELY DOES PAY OFF ON THESE RADIALS ( AND SINGLES ),WHICH RUN GLOW, TO GIVE A VERY GOOD AFTER-RUN OIL UP AND TREATMENT

As we all know running these 7-77 is quite a pain in the backside to do the after run bit..........very worth while fiddling around with the cam followers and push rods,just to get the oil in there and drain out again as necessary.
I have been using "air-line" oil after shut down,putting in approx 15/20ml,spinning the engine over,then draining the oil out,before applying "evolution blue bloc" after-run,with a final spin of the engine.I have also been using a "chain-saw" oil on the rockers for initial lubrication,being very "sticky oil"....

The FG 84 carb conversion onto the 7-77 went very well..............purchased the carb adaptor from "Morrisminimotors"....( many thanks Morris ),bought 4 x 45mm engine stand-offs and 4 x M6 countertsunk bolts at 55mm long.The 7-77 mounting plate has to be spaced more away from the radial body in order to allow the carb to fit on behind the mounting plate..hence the 45mm engine stand-offs.I also had to shorten each exhaust stubb by 10mm ( I am using the evo collector ring )....this was done so I could access the choke-pull on and slow needle adjustment on the carb ( collector ring was bang in the way !!! ). Throttle should work ok,arm and 2mm ball joint for rod will run just inside the mounting plate of the 7-77.

Just got to make another test stand now......... to see how she runs on gas.

See photos below...........may be of interest...?

Kind regards..................Nick (UK).

njmheli

Hi All.

Just a quick up-date.........made the test stand and ran the 7-77 today on gas ( Sunday ),removed all the plugs ( were running on glow ),cleaned and re-sized the gaps....all good now and clean !!!
Decided to run the fuel mix I am using on the 84,being 16:1........so a little oily !!! Needed a fair bit of priming to start with,but then fired up and had her running for around 20 minutes,non-stop until it ran the fuel tank and lines out.( using pressure feed on tank )

I have to say very,very pleased with the results..........very even idle speed,very good throttle response and transition...........cylinder temperatures were all within 6 degrees of each other.I was running a Biela 22" x 10 x 3BL...........very easily ran to 5700 RPM,with more to go,but I think that the main jet on the 84 carb may need to be set a little richer at max throttle ( just fitted carb as received from Saito as fitted to the FG 84 )..........plenty of oil in the exhaust,but expected that using a 16:1 mix.

Would definately say that running on gas is producing more "torque"...........Fuel economy appears to be great !!!!

Thank you again to "Adrian" at CH Ignitions for the supply of the CDi Kit for the 7-77......Thank you also to "Morris" at Morrisminimotors for the idea of using the FG 84 Carb and also for suppling the carb adaptor.............Great stuff !!!

So got to get the H9 Corsair finished,then back onto the T/F nearly finished Giant Corsair.........looks like the 7-77 will be bolted on that...

Kind regards...................Nick (UK).

Ted62

My Feedback: (2)

Question for Evo 7-77 owners. I plan to use the Tru Turn prop hub, I have the 2 jam nut system along with the 10mm washer that fits into the hub - special order from TT; however, any prop I have isn't thick enough to get into the threaded portion of the crank shaft. I hate to use a bunch of washers on this jewel of an engine - what am I doing wrong? I can upload pictures if needed.

njmheli

HI "TED".

Is the 7-77 going into the H9 Corsair..?

I think I know what you mean..............the 7-77 has a very long threaded crankshaft ( which is nicely suited to "thick" hub'd props..? ),but if the prop hub is not too thick,you cannot get the locking / jam-nut down enough onto the prop face...? I think most are using "Biela's" and other thick hub'd props..?

I might be incorrect here ( I am assuming that you are using a prop-hub,type B / A with the backplate..? ),but it sounds as if you require a "custom" backplate made to suite the hub with extra thickness.,to allow for the "thinner" prop-hub you have....? TT will machine you a custom hub if that is needed...

Upload some photo's for clarity...?

Kind regards.................Nick (UK).

Ted62

My Feedback: (2)

That's a good idea - I will shoot a couple pictures tomorrow and upload them here - I can't imagine I have a unique situation. Of course, I may literally be putting the "cart or prop" ahead of the "horse or aircraft) since I'm nowhere close to knowing figures. However, I try to anticipate problems and I am sure this one will require some work when I get to that area. Thanks for your help and I should get a chance to upload a shot or 2 tomorrow.

chorner

In my case with the converted engine and a biela or Mejzlik prop the backplate for the prop hub is actually too thick and I'm worried I don't have enough thread; nevermind fitting two in order to use a jam nut! Probably have to get a custom sized hub myself.

njmheli

Hi chorner.

When I received my kit of parts from Adrian for my CDi conversion,I decided to have the prop-driver that he supplied,machined,so as to remove the "grip-lines" on the face...that gave me some more length that I needed..........( a bit of a discussion on that subject !!! ),but I guess that your conversion,being a "bolt on" one,may differ from mine as the "glue on" one,with respect to dimensions after all the bits are put on...............hence different lengths of crankshaft / thread available for the jam nut etc.....I don't use a jam nut on the 7-77,just torqued up very well !!!.....stock engine only comes with a nut retainer at the end of the crankshaft as you know,being a split wire..... ( and I have never suffered from prop-slippage due to no grip-lines.......I didn't like the idea of those lines "cutting into" the Biela prop face,so I make use of the total surface area of the prop-driver face for contact............could drill and pin it if I wanted to,but no need... ).

I have been reading your comments about your 7-77 on the "care of evo....." forum...................I agree with "Maxam",they should only be a little"messy" due to the initial lubrication from the open rocker assy.
I would use some high temp vehicle sealant around those intake "tubes",if you are definately getting some leaks out of there,I used some only on the exhaust connections,just for a precaution..........BE CAUTIOUS AS THE THREADS ARE PRETTY FINE AND EASILY CROSS THREADED ON THOSE TUBES.....every where else was fine with mine.

Hope all is going well............

Kind regards...................Nick (UK).

chorner

Hey nick,

Thanks again for (yet another!) reply. Much appreciated. In regards to the CDI conversion, I would've imagined having more thread available at the end of the crankshaft but no idea with yours. I don't have exact measurements but I suppose it's enough to get a good "10 turns" of threading. If you're confident it doesn't back off without a jam nut then I'll just run it like that probably. I was thinking of contacting Tru Turn to see if they couple supply a smaller hub backplate and a jam nut combo. I too wondered about those grip lines as they are very sharp and it seemed like it might crack any sort of carbon fibre props, but they definitely hold well on mine without even fully tightening down the nut so who knows. I may keep it like that on mine.

In regards to the leaking... I agree in how easy it is to cross thread them. I'm pretty sure I did on one of mine when I pulled it off and put it back on I didn't think it'd be that easy and by the time I noticed that it felt a little stiffer putting the nut on than when I took it off it was already too late. You have to really do it with your fingers first, and then snug it up with a wrench at the end ... of course hindsight is 50:50. I've done as you said, and used some high temp sealant around all of the intake tubes. That should fix it Maybe even make it better than 'stock'. I'll probably do another round for the exhaust ports too.

I was thinking for a few minutes that I'd go nuts and try and find some flat rubber washers to fit, and some some gaskets for parts of the engine as I can't believe how many metal-to-metal connections are on this motor after opening up everything for a thorough look. It made the decision to run it with some castor oil a little easier to make, as after a good number of runs having some castor to gum things up actually isn't a bad thing in this type of motor. Once sufficiently coated, lay back on the castor and you should have a nicely sealed up and coated engine without the worry of sticky valves!

How's your 7-77 on gas, and the FG84 doing?


... p.s - what's everyone using to balance your Corsair's once completed? I also noticed David Payne mention in an earlier post he balanced his upright... any particular reason for that?

rslstft

My Feedback: (10)

I balanced the one I built at the very rearward position of the CG range and flew perfectly at that with almost no trim adjustments. I also balanced upright as it was just easier with the balancer I have.

mirored

My Feedback: (1)

I use the Vanessa CG rig for balancing my planes. Much easier to handle and very accurate.

http://www.rcuniverse.com/forum/tips...g-rig-how.html

njmheli

Hi Chorner.

Sorry for my replies and keeping you typing !!!!.......It's worth a call to tru-turn,but they may not like the idea of maching a "thinner backplate",as this may compromise the "integrity" of the backplate............but that depends on how much it has to be machined off..? ( well,that's what they said to me,as I needed a thinner backplate for my 84 set-up,but I got it machined down by a mate of mine,he also did the maching on the CDi set up on the 7-77.....on the 84,the prop-drive is held on by the crank nut ( jam nut used on the 84 ),4 bolt DA pattern to cope with the torque bit,crank nut also to hold the prop in place )...On the 7-77,as you know,unless DA pattern drilled for prop torque etc,only the crank nut holding every thing together.............hence tru-turn query !!!

If you are running the Evo collector ring....? There are SPLIT ali washers supplied with the collector ring to seal / seat the exhaust tubes in place,these are flat on one face and conical on the other.........flat face towards the inner nut surface,conical fits against the ali threaded stub on the collector ring.

The evo,from what I can see uses rubber "O" rings in various places to seal major machined surfaces...?

I have never run with Castor in any of my IC engines,..........my flying buddies only run Castor in some 2 strokes,never in any 4 strokes.......?

7-77,has only had one run as stated in earlier posts,but very pleased with the results............so waiting to see how "Bob" has got on with his gas 7-77 ..? F84,still in test stand,aimimg to get it run-in on that...........Corsair is all ready for it to be bolted on,Just gone back to the "drawing board" with the cowl,now using the stock cowl,but have moved it FWD by 15 mm...........still hoping that I may NOT need to cut any holes as yet !!!

Good question on the C of G...........hoping that all the guys fling these birds may come up with the answer and at WHAT C of G DISTANCE are they using...?

I too noticed that about David doing his balance UP-RIGHT...........just thinking where all that weight would be supported using a STD C of G balance set up or to use the "CRADLE METHOD ".......? Will have to give that some thought as it will be needing the C of G soon...!!!

Sorry again for the reply...........

Kind regards...................Nick (UK).

affas

@njmheli

Did you some temp measurements before and after gas cnversion? I do have the same engine in my Corsair with Adrian ignition but still on glow. Thinking of gas conversion but always running hoter and a little weaker..

njmheli

Hi Russ.

Many thanks for the info,very much appreciated...............what "balancer" did you use.............I'm guessing here,but to balance in the up-right position,you would have to place the "supports" very near to the wheel well areas... obviously balanced with the wheels retracted...?

Thanks again.

Kind regards.................Nick (UK).

njmheli

Hi Mirored.

Thanks also for your idea...............I had quickly looked at that,but as yet,have not got my "head" around all of the method...............did you balanace aft off the centre C of G..?

Kind regards...............Nick (UK).

Capt Midnight

Hi all...

First chance I've had to get this video posted and give you an update. I posted this video on Facebook, but this post is with a more detailed explanation.

First test run Evolution 7-77 full Gas Conversion done by Morris James in the UK. Ran 1-1/2 tanks of 20:1 Gas through it over 1-1/2 hours of bench testing. Got a nice clean stable idle at 1000 to 1200 rpm using a 22 x 10 2 blade Mejzlik prop with a brief burst to 7200 rpm at the end of the session. Most run time was spent in the 4000 to 5400 rpm range, which is the preferred sweet spot for this engine. I'll re-prop it with a 24 x 10 2 blade for test flights on the Corsair, and will also be looking at a setup from Solo Props at the Toledo Show.

The carb is a Saito FG-84 unit, purpose built by Walbro for Saito. Nothing was done to the carb other than bolt it on to the adapter supplied by Morris. The needles were left alone and not touched. Throttle response is excellent, so no further adjustments appear to be needed at this time.

The prop drive hub was drilled for me by Morris with a four bolt pattern for both the DA-50 and the DA-30. This does nothing more than keep the prop from slipping on the hub and/or flying into outer space. The Evo MUST be used with a lock nut / jam nut system as the hub is retained onto the crank using nothing more than a press fit onto a tapered collet. If the jam nuts are not used, the hub (and the attached timing magnets will slip on the hub), throwing the timing off. This will be an issue I'll look at at some point in the future, but right now it will stay as a press fit with jam nuts ( and a little locktite).

I'm using a Tru-Turn Type A Hub and spinner. With either a Biela or a Mejzlik prop, real estate on the crank becomes scarce, and I'm very close to the end of the threads using this configuration. I'm using two 10mm x 1.00 thin jam nuts, and that appears to be holding OK for now. I'll talk to Tru-Turn at Toledo about a Hud with a reccess for a jam nut. The hole in the spinner needs to be reduced; the stock size is 5mm, the crank need 4mm.

The prop thickness problem goes away if I go to Solo Props. They use a proprietary hub & adapter that is much thinner.

That's all for now. I hung the engine on the plane last night, and tonight I'll mount the ignition system.

Bob




https://youtu.be/tko831FQa0c

mirored

My Feedback: (1)

It does take a little to get your noodle wrapped around it, but once you do it, you get it. Jump in, build one, you will love it.

For the Corsair, I had it balanced at the aft CG point but I have not yet flown it. I balanced it inverted, not upright.

njmheli

Hi Alf.

Good to hear from you,no I didn't record the before temps,but I will be doing another "run" in a day or so and I will advise you as to the cylinder temps that I am getting...."Bob" may have some temp figures soon,as now he has his 7-77 back from "Morris".

As I said before,great idea that "Morris" had of using the FG 84 carb !!!! Fits on a treat with his adaptor,I was very pleased with the first run,but as said,think the mixture needs to be richer on the main jet at or approaching max throttle on my 7-77...............very even idle !!!

IMO.very worth while doing the conversion,it would be easy for 7-77 users to retro fit,just have to remove some of the 25mm mounting ply to the F/W if using that method.......


Kind regards.................Nick (UK).

njmheli

Thanks again for the info.............

Kind regards................Nick (UK).

rslstft

My Feedback: (10)

njmheli,
I too used the Vanessa sling. It doesn't seem to matter weather the plane is inverted or not, but I did balance with gear UP. It is a little confusing at first, but what I did after I built one, was take a airplane with a known good c.g. and put it in the Vanessa rig to see how it all worked. Like mirored said, once you use it, you will like it.

njmheli

Hi Bob.

Well done on getting your 7-77 running and posting on YT................sounds great !!! 7200RPM WOW !!!! a "little" over the recomended limit !!!! Not sure,but think you may now need a bigger prop to fly it.............think Alf ( aka AFFAS ) would know as he is flying with CDi on glow,pretty sure he used the 24 x10,but said that the engine was strong on CDi..and thinking of a bigger prop.,but not 100% positive on that...?

Did you manage to sort out where / how the CDi will fit in.............guess the same as chorner has done..?

Would be good to see what cylinder temps you are getting at idle and around the 5500RPM mark...?

Many thanks for the up-date...........

Kind regards.................Nick (UK).