Yeah...what Tom said. Treat yourself to a trip to Toledo. Lots of fun and your fuel too!

Photos of Ziroli Stearman 77" wingspan with evolution 7-77.
 

Figured out posting photos,
https://cimg3.ibsrv.net/gimg/www.rcu...76ab7095b7.jpg
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I don't think flying to Ohio from Florida to buy fuel will lower the cost.

Probably not!
 

A very expensive trip. To "cheapen the fuel, buy 15% nitro, 20% oil (20% castor 80% synthetic) then dilute to half with local available methanol. In Indianapolis we have a company called Jackson oil with gas pumps that distribute different race fuels including methanol. Search in your area racing fuels. three to four dollars a gallon for methanol. -Tom

Oh and lovely plane!!!!!

Is there any one with experience with the new gas radials from CH Ignitions. If so please post!!! Especially people with some hours on the engines. That 5 cylinder 75cc radial is appealing.-Tom

Happy Christmas All
Best wishes for the maiden.
Better get a hair scarf on the blonde. That mop is gonna end up in the pilots face upon run up!
Best of the new year-
Happy birthday Jesus

Maxim...could you post a picture of your starter battery. I want to copy yours and would like to know how you properly charge and build it. i believe it was three 3.5 amp hr nicads in parallel.1.5v I guess.
as you can see from pictures of my set up I need a more reliable system. Thanks very much.

I have been re reading the beginning. Of this forum to investigate a better starter battery.
I must admit I'm. Still confused.
One post states ....three 3.5 amp hr ni cads in parellel.
another reads...three 4000ml lipos with high c capacity
Then....eight 700ma in parallel
help please

For the last few years I have been using 8 700 mahr NiCds in parallel totaling 5.4 amp hr. Wires extremely short and thick!!!! Critical!!!

I would love to see how its put together. ..anything like mine??

Battery build
 

It is wrapped in tape so a picture will not be helpful.
Lay 4 cell on the bench with all + facing one way. One drop of CA between them. repeat with 4 more cells. let set. Glue the two rows of batteries together all+ facing one way making a 2x4 pack. Strip thick gauge multi strand wire like used in electric models about 3 inches back and divide the wire into two equal halves and twist some. Now solder the wire to the two rows of + terminals. Use a high wattage iron to minimize the soldering time. Repeat for the - terminals.

I'm so glad you responded Maxim.
I had similar idea but once soldered how do you charge such a pack?
That's the main reason I went with 8 batteries in holders,that way I can take apart
And charge each battery...then pop back into battery holders.
Sorry if this line of questions not appropriate here, but your the radial master
And I wanted your input. I have followed forum from 2013 when
I purchased 7-77 but was employed and building plane.
I'm retired now, plane is finished and its time to fly it.

Hitec 4-80 charger
 

Buy a Hitec 4-80. Charges all types of batteries. Right now as I type this I am charging my 2x4 glow pack at 2 amps, Transmitter NiMH at .2 amps and two 1000ma Lipo's at 1 amp each all at the same time!

Badangle, I was looking at your plane. The wires going to the glow harness, way too thin. I bet you are loosing a 1/4 of a volt. That is a lot of loss from 1.42 volts. Plus the terminals on the battery holder are lossy too. Must solder!

Hey Tom
So with your help my 7-77 runs and idles without the sonic tronic on board glow driver unit. So rather than use it as an external device for starting, i want to use your direct system. Battery build no problem and understood. Connection to engine is fuzzy.
So we have the 16 or 18 gage multi strand wire soldered to the positive cell terminals. And we have 7 leads attached to the 7 individual glow plugs on the isolated tower pin.
To use the unit.
Do we place a connector (molex pin and sleeve) between the single battery lead and the seven plug leads until the engine runs or the battery cant maintain the glow?
I am setting up the 7-77 on a BUSA Neuport 28 hull i obtained around 12 pounds (without engine). And i picked up a GP pt17 arf around 12 pounds also. It will be a test bed for a Sirus five cylinder and a Saito five cylinder i have been using as display engines. I hope to incorporate this system to avoid the on board driver unit for these two radials if they also can be run without full time glow. Yet to be seen.
This Evo is going to fly something for me, or its gonna find itself on a lexan stand.

Hy, You do have the circular wiring harness for the plugs that came with the engine? Wire that and the ground to a robust female plug mounted in a hidden spot on the plane near the engine with the shortest wire. The external battery pack you make will have the male matching plug as well as a charging plug. -Tom

What a great idea Tom. Thanks for clairification. Not used to things being so simple in this hobby 😁
Thanks

Hi I got one of these evolution 7-77. previous owner had it startet 3 times in bench only. Made a glow battery from a 7.2v 1800mAh nimh that I re solder so all the cells is in paralell. it should give me 1.2v 10800mAh and it works. had the first start today :D the engine will be mounted in a old At6 from vantex/hobby king vs 2135mm

https://cimg9.ibsrv.net/gimg/www.rcu...25bbe00f0b.jpg
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Hello, I dont always get the notification when people respond to this thread. Anyways, the gear is standard set up the original calls for an hook screw in the undercarriage with a rubber band to the cross member of the gear. I used three hooks with o-rings to make the cross member very tight to hold the gear pulled in. It works well on landing the gear does not flex much and creating a bounce. Hope that helps you out.

Mark

https://cimg4.ibsrv.net/gimg/www.rcu...0ebabe6d02.jpg
https://cimg2.ibsrv.net/gimg/www.rcu...ceb3f687dc.jpg
The 7-77 was converted to gas and Im using 23 X 12 prop, static RPM 4600 flies the plane very nicely. I modified the wing to a 3 piece, easier to transport.

Hi Guys,
I came looking for information on these engines as I have in mind te purchase of a 9 cylinder 115 gas radial. I must admit to having not read all 2500 posts on this very informative thread so I may be asking for information that has already been covered, but most of the thread seems to relate to the gas engines and their trevails. Is there any experience out there on the gas engines please?
Thanks
John

John, I have requested comments on the new generation bolt on head versions of these engines, especially the gas ones. So far, no responses. I guess Morris Mini Motors in the UK seems excited about them......Tom

Hi Tom,
I will give Morris a call but he is bound to have a vested interest. I was looking for an unbiased report. I guess I will have to wait a while. At the moment the project is just in my imagination, but I have always loved theRAF Bristol Bulldog biplane from the 1930's. Its a lovery looking machine, but like a Stearman, it hangs all of its cylinders out in the breeze and there are 9 of them. Looking at the tiny pdf on the UMS website the diameter is only 260mm, which at scale size could result in a model of around 80" wingspan. With care I think I could get this under 8 Kg or 17.5 lbs.
Having seen the original Seidel radials perform in the past, they were beautiful things, but not so powerful. So the questions if would the UMS 9 cylinder 115 Gas engine adequately power such a model? Opions welcome.

John

At that weight and wing area you will be at 1/2 throttle most of the time! A great project!