Pull Up Now!

My Feedback: (3)

For the glo plug shim idea, it might work but again it depends on how close the piston comes to the head. High compression engines have a tiny squish-band. So, with the shim, you lose some amount of thread engagement. Depending on how many, or how thick a shim one uses (based on need [piston top location]) one might strip out the threads because too few are engaging.

I have thought about how one might make a threaded bushing that could be brazed or somehow threaded onto the existing glo plug so as to engage the full intended number of threads, yet still have the plug sit high enough so as to not interfere with the piston top.

Linkan2

Hello
Excuse me if I'm a little sour
But I think that the development of parts and suport is so bad.
I have written to the UMS and the Horizon is like sending e-mail to the moon.
engines is a good product, but I have to be able to buy parts.
I do not understand that.
the next big engine purchase goes probably to another brand.
Are there any of you who have the same bad experience.
so write
Lars Lindstrom

redball8

My Feedback: (128)

I thought Wheelspinmodels in the UK carried parts - no? Or is it just a lot of shadow stock that is never really available?

Linkan2

I have paid part of Wheelspin Models.
But they have to take parts from UMS, will take several weeks.

engine has been many years in the market so they have to be able to buy parts.
Horizon has a few on their website, they are ridiculous

BobH

My Feedback: (2)

I ordered spare parts for my 7-70 before I needed them. I haven't needed them yet but I have them when I do.
Of course these aren't Major parts but the smaller ones like push rods, cam followers etc.

Maxam

My Feedback: (62)

Lars, It is my understanding that Horizon has all of the parts but only shows the very easiest ones to replace kind of like we trust you on the simple stuff to do repairs but the other parts that need replacing...send the engine to us...Comments Horizon? -Tom

Ted62

My Feedback: (2)

I have a brand new (never been run) Evo 7-77. I decided to be sure the valves were set correctly - some seemed ridiculously loose. I have removed the plugs, mounted a blank prop with a spacer, and the first turn of the motor seemed to indicated a lot of roughness. I pulled a push rod and follower in order to inject some air tool oil and that seemed to help. Does this sound normal? I've never felt a new engine that felt "crunchy". I know the factory tests the engine (according to the enclosed run test), but, maybe they didn't add any after run oil. (?) Any help is appreciated.

cymaz

If its shop bought, then let them look at it. You could have the back off yourself...but you know what that meaninvalids hop could argue that the warranty is invalid.
Though not rough, mine was very tight. Took an age to run in, it melted one starter. Now it's a beauty. Always run it out bone dry then put a good amount of after run oil in and span it up to get the oil everywhere inside.

njmheli

Hi All.

Looking for some advice here..............I have had my 7-77 running on glow,with CH Ignitions CDi..................very sweet and running very well,although it has only been run in the test stand for around 4 1/2hrs total...............I am running a Biela 22" x12 x 3BL prop on it and at the moment the last full throttle run ( ground RPM ),using the Rxcel Tacho,that plugs into the CDi box...........I was getting around 5100RPM..........still on the rich side at max throttle..........

I would like to convert this 7-77 to run on petrol ( gas )..............has anybody had any problems with this.....?

I have seen that the carb from the FG84 will run this 7-77 and appears to work very well.............my thoughts are that a little more torque will be produced,hence a few more RPM's at top end ( still allowing as safe margin on max RPM in the un-loading in flight )as one expects..? ).........The advantages being,fuel economy and a little less mess and doing away with all the after running procedure.........?

I would assume that a fuel mix of say 20:1,would be a good starting point............?

Morris Mini Motors,here in the uk does the conversion complete or you can purchase the items from him and complete yourself,I would guess..?( in my case just need the carb adaptor for the 7-77 fitting ).............video is up on YouTube,showing a 7-77 running on gas...........

Would be interested to hear your views / comments...?

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

BobH

My Feedback: (2)

Nick,
since glow fuel is combined with oxygen faster than petrol thus producing a little more power, why do you think you would get more torque?

Ted62

My Feedback: (2)

The engine was purchased directly from Horizon Hobbies. Rather than return it, I guess I'll continue with the break-in (I hate that term) procedure - I suspect there was some surface rust somewhere - I suspect the cam - going to flood the inside with after-run oil and look at what comes out. If it's really disgusting, I'll give HH a call. Thanks for the comment - we need spring here in Pennsylvania, USA., really badly!

njmheli

Hi Bob.

Many thanks for your reply,yes,understand about the glow fuel and having it's "own" oxygen content in addition to what the engine "sucks" in..........I may be under the incorrect assumption here that gas engines are able to swing bigger props...?..........on my gas engines,I have compared to the glow ones I have,being of the same capacity cc wise,the gas engines run bigger props..................hence my thinking that this must be the result of higher torque ( talking 4 strokes here )...?

Knowing that glow does produce more power it it's "bang" as opposed to gas in a similar capacity.............hence a gas engines will be of a higher cc than their glow counterparts,again talking 4 strokes...?

The Saito FA 450R3..........75cc ( Glow ),great power output...............FG 84 R3.........84cc ( Gas )..........again great power out put,but more cc required for that.

I may have got this totally wrong !!!...............But interested to hear from flyers using any seidal / evo 7-77 radial running on gas.....

I guess the only way is to do the conversion and see what the figures would be from one to the other.......

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

BobH

My Feedback: (2)

Nick,
Energy is energy. All other things being equal more energy wins, at least that's how I see it.

redball8

My Feedback: (128)

Energy isn't everything - the rate at which you're able to access that energy is power, and usually folks are after power.

Alcohol fuels have lower specific energy content (Btu/lb), but they run so much more fuel per unit of air (5:1 vs. 15:1 for gasoline) that they wind up producing about 20% more power, all else being equal. See SmokemUp, for example. I like his summary - "Gasoline is for washing parts, alcohol is for drinking and nitro is for racing."

BobH

My Feedback: (2)

I should have said.. Available energy at the time of combustion

redball8

My Feedback: (128)

No worries, Bob.

njmheli

Hi redball8 ..................Thanks for that and love the summary !!!!! ......................

Cheers !!! Nick (UK).

chorner

Does anyone know the mounting bolt thread/size? I'm wanting to use the inner holes, and the bolts that hold in the standoffs thread into them - just want to know the size before I go out to the shop and buy some bolts without guessing

EQ1

(deleted)

garyFL

I have the 7-35 mounted on an engine stand. I installed and tested the Mcd477-4.8V Pulsed On Board Glow Driver. I'm having a problem getting it to fire. It doesn't seem to be getting fuel to the cylinders. How long do I need to choke it when cranking with an electric starter? Oh yeah, I'm using 90/20 methanol and oil mix. This is my first radial and I'm sure it is something I'm doing wrong. Any help would be appreciated.

GaryM

redball8

My Feedback: (128)

Fuel coming out the exhaust pipes is a good sign the cylinders are getting wet. Did you mean 80/20, or 90/10 for the fuel mix?

garyFL

Sorry, I meant 90/10. At full choke, about how long cranking before I should expect to see fuel coming out the exhaust?
Thanks for your help, Gary M

redball8

My Feedback: (128)

Shouldn't take but 5-10 seconds max. Depends on tank height relative to carb, of course, and any restrictions in the line (filters, etc).

Maxam

My Feedback: (62)

Guys. Personally I would never have the choke on and use an electric starter. With the choke on I do about 5 flips of the prop by hand max! The engine will flood out and can hydraulic lock with that much fuel drawn in.

redball8

My Feedback: (128)

Good point ...