Is this ignition cutoff switch something I forgot to order , or is it a luxery? Thanks

A "Kill Switch", whether it is the form of a "fuel interrupt" (Line pincher - hardly EVER used anymore), a "flood carb" (Choke servo- operate to close venturi), or "elec kill" (either a switch operated by a servo, or an electronic module that switches off the igntion battery using solid state current control like an ESC, or a relay, like this Dim Eng stuff) are, in my mind, the IMAA (for whatever that is worth) and the good ol' common sense guys who are concerned about safety ---- NEVER a Luxury, but rather, an essential part of flying an overpowered gasser with a direct, solid, throttle pushrod to a hard mounted motor.

The rationale is that throttle servos fail. It has happened to me before. Sometimes fails LOW, engine dies, sometimes fails HIGH, full throttle, and that ain't good. Most of us carry fuel that would exhaust batteries before the tank empties. Most 3D type airframes these days are so grossly over-powered that they likely would not tolerate or survive an extended mission at full throttle, all other things being equal.

An engine-stopping device operated by the transmitter solves that issue. Had a flight the past summer where the throttle pushrod had stripped...couldn't idle low enough to land. Without a kill choke (on that airplane), I would probably still be flying around out there just a notch above idle, staggering through the wind.

Whatever device you decide to use, to many of us, a "kill option", is not really a luxury, it is simply another safety component that we want to have on board to keep things relaxing. (There is a LOT of tension and stress involved if you have a throttle servo failure)

i use that fiber optic kill switch, its nice, has an led when power is on, i use it all the time, when i 1st set up my throttle linkage i couldnt get it to kill, even with the trim all the way down and using the throttle cut feature on the radio, it just kept idling, extremely low, but not stopping on its own, so that swicth came in handy, its the way i would go from now on, its easier than setting up another servo for choke, as long as you can reach the choke arm or set up a pushrod sticking out from the cowl to choke when you need it, (starting) then go with an electric type kill i'd say

I enjoy different opinions, but on this one, I have to say that NOT HAVING some kind of transmitter-operated definite KILL method is a BAD choice. If a person doesn't want to buy the Fromeco (or other) type of switch, fine, but then HOOK UP A CHOKE SERVO. We simply MUST have a separate method of killing these things besides the throttle while they are airborne.

It has never been "dictated", but I don't know why anyone would NOT do this.....

Just my opinion, of course.

BTW - those here that are using the DX 7 Spektrum - I've just posted a page on my website about the DX 7 and will update it frequently. http://www.rcaerobats.net/Spektrum/s..._main_page.htm

i think mine was called smart fly, or something like that, i'd have to look through my manuals, but i agree with you bob, i did have a servo(linkage) go bad on a glow plane once, i just flew it around until it died, i would not want to do that with my big gasser...

I had problems ordering the combo so I went ahead and ordered the EVO45. Maybe I'll get the same performance as in the vid

aerobob,

Enjoyed your web site covering your work on the Yak 54 Brillelli 46 combo. I have done about all I can on mine before tackling the job I hate worst. That is mounting the engine and cutting the cowl. What I would really like to see are some close up pix of the cowl and the cut outs required to clear the engine head, the side-mount muffler, and possibly the carburetor. It looks like the carb will be very close and there will definitely be a clearance problem with the choke lever as supplied and no room for that nice inlet horn that comes on the carburetor. Also, to avoid weight in the tail and tail mounted battery packs it looks like the engine could mounted about a half inch closer to the firewall than called out in the instructions ( 6 inches instead of 6.5 inches to the prop drive washer). What do you think about that? I just can't stand the thought of cutting up that beautiful cowl and making a mistake that will make it ugly.
One other thing, I could not see how you are operating the choke, maybe another close-up of that area would be helpful. Thanks for all your comments thus far, keep them coming [8D][8D]......Bob C

Bob - I'll be happy to do more detailed pics (supposed to, anyway).... and will. Some of the answers...
1. Engine mounted flat to firewall, no spacers, at about 6". Cowling not a problem going back further
2. HEAD *DOES* clear inside the cowl. Plug cap connector, choke, and muffler need holes access.
3. Operate the choke with a small, straight blade screwdriver. I cut off the "arm", slotted the nylon shaft, glued on a small "collar" of brass tubing so the screwdriver wouldn't cam out when turning. Accessed through a hole in the cowl, it doesn't protrude. Neither do the carb adjustments, just a hole to get to them.
4. Carb arm - clears just fine.

I aligned the motor per the measurements in the manual, life is good. Fits very well.

Cuttting the cowl is very important; there needs to be air getting OUT of that big bowl, and heat build up could be a problem. My pics will show how I addressed that, I hope.

Thanks for the comments.

Allright here are some pics. If this doesn't look "elegant" enough for some, please skip this post. I'm not after "form", I'm after FUNCTION, and that means air exit opportunities. And reasonably-directed IN flow....so here's mine. Very similar to how I did that "other" 73" Yak (RIP)....

Thanks aerobob. Call me a copy cat.

Aerobob,

Thanks much for your efforts, I,m still not going to enjoy cutting up that cowl but your pictures will make it much easier.
Thanks again.[8D][8D]......... Bob C

PM me if you need more exact dimensions. The muffler opening APPEARS to be too wide, but that was needed to allow the cowl to be installed WITH the muffler on the engine. The angle of the cowl front/engine hub down to the rear-most exhaust tip is what drives that. Difficult to explain, but hope this helps.

FWIW - Carving on a cowling is also WAY DOWN on my list of "things I enjoy".... also.... It seems just so WRONG to do....

Looks like you can chop some of the pipe and reduce weight.

***??????
You talking to me?

WHY would I cut the exhaust pipes off on this muffler???

You can cut on yours, thank you.

DO I DETECT AN ATTITUDE> Look I am here to learn how to set up my planes the best way I can. You have been giving good advice so far compared to others. I would not give advice to anyone unless I heard, seen, or have done-it myself! [:@]

Wow.
Let me put this carefully, so as not to offend....

THERE AIN'T NO FREAKIN' REASON TO CUT OFF THE MUFFLER EXHAUST TUBES....

If I ever get that anal about weight on a gas engine airplane project, I'm afraid I'll have to give up the game.

But thank you for the suggestion.

No offence taken! Keep up the good work!

anyone use the pico switch that was posted a couple pages earlier?looks good but not sure if would handle vibration?

FLYMIKE, the total muffler weighs 2.3 oz, so there isn't much weight savings in cutting the pipes.

Bob, the Bisson mufflers with the rolled tips BEG to have the pipes cut. That is ONE good reason to cut the pipes This muffler with straight pipes doesn't obstruct flow the way the tips on a Bisson muffler would.

the plane looks great Bob. When will you get out and fly it?

I am also tired of being grounded for winter. Most of the nicest planes are now ARFs, so "building season" has lost it's meaning.

bob that looks like nice work to me, i take the "function" aspect a bit further myslef, i have been known to hack a new hole in a cowl at the field with a dull exacto knife to get at something easier, i think yours looks very nice

Boy is that the truth..now I call it "putting together" season.....

I must admit - those Bisson's with those STUPID rolled tips have ALWAYS been cutoff, but not for weight reduction, but rpm increases. Can't believe he still does that after all the guys that have cutoff all these rolled ends.

Increasing RPM - now THAT is a good reason to cut ANY tube....

Brett - the wx has been very un-flyer-friendly the past couple weeks, or longer. And nothing flyable in the short term forecast.
Having this thing all dressed up and no dance to go to....well.... it SUX.