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David_Moen · 08-30-2004, 05:16 PM

I had the opportunity to find out just how long an MVVS 1.60 gasser will run on 16 ounces of fuel yesterday....I didn't really plan it that way but I learned a few things and drove home with an airplane that was in the same number of pieces that it came to the field in....

Standard flight plan for me, 16 minutes of yank and bank untill the timer on my TX tells me that my eyes are going to get tired sometime soon...bring the Ultra Stick in on approach and everything is normal until I cut the throttle to idle for landing, and it doesn't go to idle!!! Even more butt-puckering is the fact that it doesn't power up for a go-around! It just putt-putts right down the runway about 5' from the deck as happy as it can be. With no apparent throttle control I gently bank out of the pattern and circle up to give me some thinking time. I have no throttle control, and my throttle-cut switch is completey ineffective. The engine is running along at about 1/8 throttle, enough airspeed that there's no way I'll be able to land and ground-loop, nor can I stall the engine by pointing the nose straight up or straight down, it just keeps plonking along. I decide there is nothing to do but wait it out. Turns out I wated another 42 minutes before it runs out of fuel. The landing is uneventful. Turns out the nylon ball-link I had on the throttle arm popped off. I had disabled the throttle return spring so that the servo wouldn't be fighting it so when the linkage came undone it just stayed where it was.

What I learned....

I got lucky that this didn't happen at full throttle!
Don't use nylon ball links for throttle linkages on gas engines....
Have a secondary engine kill device so that your airplane can be shut down in an emergency....
Gas engines are very fuel efficient!

AJCoholic · 08-30-2004, 05:30 PM

Thats why (as well as having a secondary shut off) I also leave my springs on the walbro type carbs on - I figure if that happens the engine will go to idle/cut and the little bit of resistance is nothing for the servo to overcome.

Thankfully you got your plane down OK and in one piece! I had that happen to me with glow engines before

nony · 08-30-2004, 05:51 PM

That is impressive!! Good think the batteries out lasted the fuel too!

Nuker · 08-30-2004, 06:21 PM

So did someone at least come by to chat while this was going on? 42 minutes is a long time (+ 16 to start) to be staring at a plane.

Glad to hear it ended up safe.

Bob

BrianDallas · 08-30-2004, 06:30 PM

So..............I can get by with a 6 oz. tank in my 1/4 scale Decathlon !!!

WildBill · 08-30-2004, 08:05 PM

Funny thing Dave, i was out flying my edge tonight and the same thing happened, almost. went into a flat spin(beautiful i might add

) and when i applied throttle to come out nothing happened

, it came out of the spin with no problem, but as it was coming on the down line the throttle jumped up, i leveled out and started thinking, "what do i do now", so i pulled vertical, and the throttle dropped to idle, i leveled out and started a landing approach and i hit the choke to kill the engine,(in case it decided to jump up again), unfortuately i hit it too soon and camne up short of the runway

, so i am about to start putting the landing gear back in it. It turns out the throttle servo mounts broke loose

, so i am going to make one out of aluminum like the ones that some one showed here on rccanada. It is too bad, it was agreat night to fly, and now i will be out 2 days of practice for london while i fix it

Vulcan1 · 08-30-2004, 08:23 PM

I think with the gassers we are carrying away to much fuel. On the side I use a second small servo on an aux. channel with a fine wire with loop over a toggle switch. It is hooked up to the kill post and ground. Double the kill when airborne. The small micro is mounted to the front of the firewall on a alum. bracket.
John

WildBill · 08-30-2004, 09:11 PM

i am going to install an optical kill, after today i think i will put them on all my gassers

David_Moen · 08-31-2004, 12:22 AM

It was a long flight! I don't have a neck strap so the TX was even starting to get heavy! There was a rain squall and the wind had time to change direction about 4 or 5 times too. Given the time, here was enough time to have the failure post-mortemed long before the wheels touched the grass as well!

I left a kill switch out on this airplane wanting to keep things simple and light. I just read a blurb in RCM about a teensy weensy TX controlled ignition switch that is probably lighter than my existing switch anyway. Next plane will have it for sure. In the mean time I'm going to re-engage the throttle spring and put a proper ball link on the carb!

08-30-2004, 05:16 PM	#1
David_Moen Guest Join Date: Nov 2003 Feedback: 0 / 0% Posts: 280 Total Props: 0	Unitentional mileage testing.... Remove this ad - become a site supporter! I had the opportunity to find out just how long an MVVS 1.60 gasser will run on 16 ounces of fuel yesterday....I didn't really plan it that way but I learned a few things and drove home with an airplane that was in the same number of pieces that it came to the field in.... Standard flight plan for me, 16 minutes of yank and bank untill the timer on my TX tells me that my eyes are going to get tired sometime soon...bring the Ultra Stick in on approach and everything is normal until I cut the throttle to idle for landing, and it doesn't go to idle!!! Even more butt-puckering is the fact that it doesn't power up for a go-around! It just putt-putts right down the runway about 5' from the deck as happy as it can be. With no apparent throttle control I gently bank out of the pattern and circle up to give me some thinking time. I have no throttle control, and my throttle-cut switch is completey ineffective. The engine is running along at about 1/8 throttle, enough airspeed that there's no way I'll be able to land and ground-loop, nor can I stall the engine by pointing the nose straight up or straight down, it just keeps plonking along. I decide there is nothing to do but wait it out. Turns out I wated another 42 minutes before it runs out of fuel. The landing is uneventful. Turns out the nylon ball-link I had on the throttle arm popped off. I had disabled the throttle return spring so that the servo wouldn't be fighting it so when the linkage came undone it just stayed where it was. What I learned.... I got lucky that this didn't happen at full throttle! Don't use nylon ball links for throttle linkages on gas engines.... Have a secondary engine kill device so that your airplane can be shut down in an emergency.... Gas engines are very fuel efficient!
	.

08-30-2004, 05:30 PM	#2
AJCoholic RCC Supreme Contributor I am: Andrew Coholic Join Date: Sep 2002 Location: Timmins, Northern Ontario Radio of choice: JR 12X, 28X Feedback: 47 / 100% Posts: 12,277 Total Props: 61	Thats why (as well as having a secondary shut off) I also leave my springs on the walbro type carbs on - I figure if that happens the engine will go to idle/cut and the little bit of resistance is nothing for the servo to overcome. Thankfully you got your plane down OK and in one piece! I had that happen to me with glow engines before __________________ Andrew Coholic -MAAC #26287L 1/2A to giant scale, IMAC, SAM, R/C sport, turbine jets, Heli's... if its got a wing or two and an engine - I like it!
	.

08-30-2004, 05:51 PM	#3
nony RCC Supreme Contributor Join Date: Sep 2002 Location: the Park, Ab. Feedback: 0 / 0% Posts: 4,339 Total Props: 0	That is impressive!! Good think the batteries out lasted the fuel too! __________________ Wayne The sooner you fall behind, the more time you will have to catch up.
	.

08-30-2004, 06:21 PM	#4
Nuker RCC Supreme Contributor I am: Bob D. Join Date: Aug 2002 Location: Whitby, Ontario Radio of choice: Futaba 12FG # of RCs: 1+ Feedback: 0 / 0% Posts: 3,312 Total Props: 0	So did someone at least come by to chat while this was going on? 42 minutes is a long time (+ 16 to start) to be staring at a plane. Glad to hear it ended up safe. Bob __________________ Bob D. Ajax RC Club Indoor Aero-Choppers Member of MAAC since I joined Lighten Up, Life is waaaaaayyyy too short
	.

08-30-2004, 08:05 PM	#6
WildBill RCC Expert Contributor I am: Bill M Join Date: Nov 2003 Location: Kitchener ON. Feedback: 2 / 100% Posts: 886 Total Props: 0	throttle Funny thing Dave, i was out flying my edge tonight and the same thing happened, almost. went into a flat spin(beautiful i might add ) and when i applied throttle to come out nothing happened , it came out of the spin with no problem, but as it was coming on the down line the throttle jumped up, i leveled out and started thinking, "what do i do now", so i pulled vertical, and the throttle dropped to idle, i leveled out and started a landing approach and i hit the choke to kill the engine,(in case it decided to jump up again), unfortuately i hit it too soon and camne up short of the runway , so i am about to start putting the landing gear back in it. It turns out the throttle servo mounts broke loose , so i am going to make one out of aluminum like the ones that some one showed here on rccanada. It is too bad, it was agreat night to fly, and now i will be out 2 days of practice for london while i fix it __________________ There is no such thing as too low Team Yak Team "M"
	.

08-30-2004, 06:30 PM	#5
BrianDallas Guest Join Date: Oct 2002 Feedback: 0 / 0% Posts: 151 Total Props: 0	So..............I can get by with a 6 oz. tank in my 1/4 scale Decathlon !!!
	.

08-30-2004, 08:23 PM	#7
Vulcan1 RCC Supreme Contributor I am: John Davidson Join Date: Feb 2003 Location: Vulcan,Alberta Radio of choice: EVO(12), Futaba # of RCs: ? Feedback: 0 / 0% Posts: 2,927 Total Props: 0	I think with the gassers we are carrying away to much fuel. On the side I use a second small servo on an aux. channel with a fine wire with loop over a toggle switch. It is hooked up to the kill post and ground. Double the kill when airborne. The small micro is mounted to the front of the firewall on a alum. bracket. John __________________ John Davidson Keep the shiny side up and the wheels down
	.

08-30-2004, 09:11 PM	#8
WildBill RCC Expert Contributor I am: Bill M Join Date: Nov 2003 Location: Kitchener ON. Feedback: 2 / 100% Posts: 886 Total Props: 0	engine i am going to install an optical kill, after today i think i will put them on all my gassers __________________ There is no such thing as too low Team Yak Team "M"
	.

08-31-2004, 12:22 AM	#9
David_Moen Guest Join Date: Nov 2003 Feedback: 0 / 0% Posts: 280 Total Props: 0	It was a long flight! I don't have a neck strap so the TX was even starting to get heavy! There was a rain squall and the wind had time to change direction about 4 or 5 times too. Given the time, here was enough time to have the failure post-mortemed long before the wheels touched the grass as well! I left a kill switch out on this airplane wanting to keep things simple and light. I just read a blurb in RCM about a teensy weensy TX controlled ignition switch that is probably lighter than my existing switch anyway. Next plane will have it for sure. In the mean time I'm going to re-engage the throttle spring and put a proper ball link on the carb!
	.

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