marvair

Hi there gents,

I am the unhappy owner of a SAITO FG-40. For the past 4 years... I shelved it two years and dusted it off over the winter to fit it on Hangar 9 Spitfire "30cc". After finding the ignition lipo 2S have a weld broken (intermittent 8.4V to 4.2V) and find out that 95E dose not work very well... I fed it 98 gasoline and it work fine on ground but in flight it sounds like it misfires or the cooling is not sufficient and it stops in flight. I open-up cowl exit vent and reopened the front + baffled the cylinder. Well it still misfires and some time it stops...
Now i have fitted a new stock carburetor the same things are happening... I am down to point the ignition system (original from Saito). I do know that these engines have a tendency to play hard to get but dam this one is give me a run for my money...
I can not find a reference for ignition box for Saito FG-40. (they are probably ashamed or out of stock...)
How do you see this problem on FG-40. Have you encountered such inquiry? Would you give me some tips on how to trouble shoot?
The new neither the old carburetor can not suck gas when trying to prime/chock when the fuel lines are empty on the first start of the day... I have to put my finger in the intake.

I could be the problem not understanding fully how it works… I will not quit until it works properly!

I ordered a new ignition system from CH Ignition to test it it could be the ignition


Regards

Marv

ForcesR

Marv; you are wasting hard earned money, you do not need a new ignition. I have an FG-36 installed in the H9 30cc Spitfire and it acted exactly as you described, sputtering and coughing in flight but not on the ground. Mine began sputtering and coughing around the 5 minute mark into 10 minute flights. I never had a dead stick, as soon as the sputtering started I landed. It took me a while before I isolated the problem.

I did a bit of trouble shooting/testing and found that the reason for the sputtering and coughing during flight was due to stagnant hot air that the carburetor was sucking in. I solved the problem by installing an air dam on the bottom of the cowl at the leading edge of the hot air exhaust hole. The sputtering and coughing completely disappeared on the first flight after dam installation and has never returned.

The FG-36 was purchased in 2009; I had it installed in a P-51 Mustang but changed it out and installed it in the Spitfire. The FG-36 has run like a well oiled machine since 2009 and has never failed to start, it runs perfectly and does not burp/cough anymore on takeoff as most owners have reported. Everyone at the flying field is impressed with how nice the H9 Spitfire looks in flight and the awesome sound of the FG-36.

Roger

marvair

Hi, Thanks,
Any pictures?

I severly damaged my H9 Spit. It did not land where corn is thick... It is reaparable but it will take a very long time. I will give it to a les fortunate club member. H9 are sold out cant buy a new one. But I found a nice alternative for the same money. My E-FLITE gear will fit with some light modification.

http://www.bigplanes.nl/contents/en-...uig-plane.html

Regards,

Keep your stick on the ice!!! :-)

ForcesR

Marv; sorry to hear that the H9 was damaged. The FG-40 would be ideal for the new composite Spitfire and installing an air dam will eliminate the chance of hot air being sucked into the carburetor and causing a dead stick. With the confined space in the cowl of a Spitfire, a dam is a must to draw the hot air out of the cowl especially if you're using a Saito 4 stroke gas engine.

I will post some photos of the H9 Spitfire cowl, air inlet, hot air outlet and the air dam/spoiler when I get home this evening.

Roger

ForcesR

Good day Marv; I could not download pictures of the air dam/spoiler from my camera last evening. The camera is on the fritz for some reason, it's an older Fuji digital so I think it's time to upgrade to a more modern digital camera. As soon as I purchase a new camera I will take photos of the dam/spoiler again and post them here.

Roger

marvair

No rush Roger,
Nice thing take time!

A+

ForcesR

Hi Marv, my Fuji camera is now working for some unknown reason it wouldn't down load photos two days ago. Here are the photos of the cooling air inlet, hot air exit and air dam/spoiler.

Roger

marvair

Thanks Roger,
I had a similer venturi air dam on the sides 3 cm X 1.5cm. I think to install an air duct to supply cool undisturb air from the fuelage.

Is your carb dificulf to prim on the first start of the day. My carb will not pump the air in the line to draw fuel. I have to put my finger in the intake to prime.

ForcesR

Hi Marv; I prime the carb for the first start of the day using the choke extension tool as shown in the photos. I close the throttle and then screw the extension tool into the LSN throttle barrel, pull the tool until the spool is extended all the way out then use a small clamp to hold the extension tool. I manually turn the prop a full 5 rotations to prime the carb. I then remove the clamp and extension tool, open the throttle via the transmitter to a low idle setting, turn on the ignition and flip the prop to start the engine. The engine will start 95% of the time on the first flip, if it doesn't start on the first flip it will start 100% of the time on the second flip.

Roger

marvair

Salut Roger,

I doo prety much evrething by the book and the priming procedure does not draw fuel. The finger in the trumpet does..

ForcesR

Salut Marv; if you are using the choke extension tool and the LSN throttle barrel spool is extended all the way out and held until priming is completed. You also have to ensure that the throttle is closed/off, and the throttle trim switch/slider is also closed/off. The engine has to draw fuel in this configuration! It will draw fuel into the carburetor the same as having your finger covering the trumpet.

Roger

marvair

Guten Morgen Roger,

You have a point here..."throttle trim switch/slider" I was letting it at the same position as when i flick the kill SW off.
Saito gas engines are like computers...most problems are between the keyboard and the chair!!!


Thanks for your input.