RCU Forums

RCU Forums (https://www.rcuniverse.com/forum/)
-   Gas Engines (https://www.rcuniverse.com/forum/gas-engines-142/)
-   -   Let's try again DL-50 (https://www.rcuniverse.com/forum/gas-engines-142/5532868-lets-try-again-dl-50-a.html)

Stick Bender 07-11-2007 11:03 PM

RE: Let's try again DL-50
 


ORIGINAL: Kevin Greene

On my JR 10X my choke is on the twist knob above the throttle stick---No way to accidentally flip a switch to activate it...;)---You have to conciously turn the knob...

Kevin
I might do that now, since I bragged about never hitting the wrong switch, I'm sure you can guess what happens next flight ;)

jrjohn 07-12-2007 08:53 AM

RE: Let's try again DL-50
 


ORIGINAL: Stick Bender

a buddie box won't help if you have corn on the approach, or will the buddy box quickly remove all corn stalks?

thats what I call a real buddy! I was just reading a couple days ago about a guy that flipped his choke by accident on final and crashed. I don't use a choke servo, too much extra weight and one more weak link in my opinion. This is America so please, do as you wish.

John
[/quote]

A lot of thought went into the switch, the only switch I use on final is an idle down switch. It's right above my choke switch (top left on a 9CHP), If I try to pull the choke switch back instead (which has never happened) It don't matter cus that's choke off and it's already in that postion. I use 7 switches on my Extra and never flipped the wrong one, I know what every switch does and there is one I'm not using.(Timer,Elev,Ail,Rudder,idle down,choke,engine kill)

The choke servo is also my backup engine kill (a very good safety item on a gas engine if you ask me) and a 27% Extra 260 at 13.7 lbs dry is not heavy. Most of the ones I have read about came in close to 15 with a 50 and they say the plane flies just fine, I know for a fact mine flies just fine. It's a real crowd pleaser [8D]

1.3 extra ounces could save a life or an airplane, how much is your life worth? How much is your plane worth?
[/quote]

I got my life for free, the plane is about $2500. There was one time when I wished I had a choke servo. On the maiden flight of my 87'' EF yak, the throttle servo decided to lock up with nearly a full tank of gas. It's no fun flying like that. I felt like I was flying a warbird.

John

remcl1 07-12-2007 05:05 PM

RE: Let's try again DL-50
 


ORIGINAL: jrjohn


ORIGINAL: remcl1



ORIGINAL: jrjohn



ORIGINAL: aerobob



ORIGINAL: Stick Bender

I used a servo on my choke, not sure if anyone else would want to do this as it requires a small carb modification.

I took the coke plate loose and removed the shaft CAREFULLY, there is a spring loaded ball and detent that are needed for manual choke but makes it to hard to turn for a servo (in my opinion) I removed the spring and ball and reinstalled the plate and shaft, I used a standard size servo but a micro like a hs-81 would be plenty and an hs-55 might be enough. It just needs to hold the plate open or closed. I love it because I never touch the plane except to flip the switches and the prop. Use a switch you won't hit in flight, because a closed choke will kill the engine.
What did you do about damage to the shaft from removing the swedged screw in the choke plate shaft? I was (and am) fearful of screw ingestion, so I left my detent in place, and went with a rod to the front which I reach through the cowl opening next to the prop hub.
I hope he loctited the screw, if not we could have our first engine failure. I like a manual choke from the front like Aerobob. It's lite, fool proof and I don't have to worry about flipping the choke switch when I'm on long final and crashing

john
If you are on final (even a long final because you will have more altitude) and your engine quites, I really hope you would not crash. If so, time to get back on the buddy box.

a buddie box won't help if you have corn on the approach, or will the buddy box quickly remove all corn stalks?

thats what I call a real buddy! I was just reading a couple days ago about a guy that flipped his choke by accident on final and crashed. I don't use a choke servo, too much extra weight and one more weak link in my opinion. This is America so please, do as you wish.

John

I guess if you are eating corn while on final that may distract you enough to crash.

In all seriousness, my point is you should never be so low that if you dead stick your plane does not have enough altitude to make it back to a safe landing area. Does not have to be the runway, but should not be in a corn field either.

dammud 07-12-2007 09:33 PM

RE: Let's try again DL-50
 
"I have run choke servos on five different gas engines including the DL50 and never modified the ball spring etc. I set the servo with the atv and the ball and spring hold the choke at open/closed position and the servo just gets it there. As does the rod pull through the front of the cowl. Why take the carb apart and remove parts? 3-d guys for weight savings?"

Maybe you haven't tried doing it with a mini servo as he did. It won't close all the way. Not enough torque to overcome the detent! (Been there, tried that.)

Ken

skreamer 07-12-2007 09:45 PM

RE: Let's try again DL-50
 
I tried the mini servo on the throttle and choke and MY mini servos did not last very long. MY understanding was to not use servos with nylon gears on a gasser. Now I use servos with metal gears and and they have plenty of tourqe.

Kevin Greene 07-13-2007 12:16 AM

RE: Let's try again DL-50
 
1 Attachment(s)
If you look at my throttle servo it is a standard BB servo w/plastic gears---The choke servo was what I had laying around and although it is classified as a small servo it actually puts out more torque that the full size standard servo by about a third...It also costs almost 3 times as much...Plastic gears are fine--It is the brand of servo and the quality---Not necessarily the size that matters....I used the stronger servo on the choke due to the short arm of the choke---I wanted to be sure that I had enough power....The smaller servo actually has a much stronger gear train due to the thickness of the gears....

Kevin

XJet 07-13-2007 01:18 AM

RE: Let's try again DL-50
 
I find plastic gears are better for throttle servos -- although there are lots of vibes there's not much in the way of real shocks and the nylon doesn't wear anywhere near as fast as metal.

Of course I guess I could just throw another 5955 on throttle but that would be a stupid waste of money (or would it? Hmmm...:-)

jetstuff 07-13-2007 03:09 AM

RE: Let's try again DL-50
 
The only possible reason I can see to fit a choke servo, is if you have remote electric start too..... if you have to bend down to flick it.... then click it too....the choke that is.....;)

john

Kevin Greene 07-13-2007 08:18 AM

RE: Let's try again DL-50
 


ORIGINAL: jetstuff

The only possible reason I can see to fit a choke servo, is if you have remote electric start too..... if you have to bend down to flick it.... then click it too....the choke that is.....;)

john
With a rear carb engine like the DL50 it can be difficult in some situations to get to the choke...I know that I can't get to the choke on my DL50 powered Chip Hyde Vision due to the carb partially protruding through the firewall...Vitually impossible...The only way is to run a rod into the hatch area, but who wants to choke their engine and then screw on a hatch???

However, since I started putting servos on chokes I have never gone back to manually flipping the choke lever except for engines with a side mounted carb which are easy to access...Very easy to turn a knob on the TX!!!....And c'mon....Those of you that say they can feel the weight difference when flying of another 1 1/2 ounces that the servo adds....You're from another planet!!!:D

I wonder how many DL50's are in the USA now???

Kevin

Bob Pastorello 07-13-2007 08:28 AM

RE: Let's try again DL-50
 


ORIGINAL: jetstuff

The only possible reason I can see to fit a choke servo, is if you have remote electric start too..... if you have to bend down to flick it.... then click it too....the choke that is.....;)

john
One additional - and Important - reason to use a choke (for those new to gas, particularly). If one chooses to NOT buy one of the electronic ignition cutoff gadgets as a "kill", then it is VERY handy to be able to flick the choke switch and kill the engine. Not for routine stuff; that's not a good plan. But when you NEED to stop the engine for some reason, a choke servo permits that.

A few pages back I posted my pic of my "kill switch", which is a NC lever-microswitch attached to the side of a Hitec HS55 servo. Red wire is connected to the NC position of the lever switch, then when the servo is actuated, the arm pushes the lever down, opening the circuit to the ignition.

I chose this setup because I couldn't (too lazy) engineer a choke servo easily on this GP Cap 232 that the DL is mounted onto.

Having a kill switch that is NOT the throttle servo, or throttle trim/pushrod is a good safety precaution I like to recommend to folks.

Snaer810 07-13-2007 09:17 AM

RE: Let's try again DL-50
 
Hey Guys,

Well I guess I'll add my two cents.....:D I'm the other guy with the P51 warbird installation.....LOL

I took Boss's idea and just made up a simple tool made of some metal push rod material. Added a 1" 4-40 bolt double nuted to the choke arm so it would extend out from the carb a bit and also give me a little more leverage.

I'm able to slide the tool all way to the choke arm through the air intake at the bottom of the cowl and easily flip the choke in either direction. I'll also be adding an electronic ing. kill switch just for safety sake.

I think it just comes down to personnal preference actually.

But I know being new to the gas engine scene that I will not be tearing into the carb to make mods etc. until I have quite a bit more experience.............:)

Mike

Bosshossv8 07-13-2007 10:57 PM

RE: Let's try again DL-50
 
WHATEVER WORKS ...

As devil's Advocate..............


While a choke servo is a great convenience, it is not a substitute for a kill switch...as Bob said, if you NEED it ..it can suffice as one, for sure.

Depeneding on orientation, a loose motor could make it in-effective, all the while pulling your throttle open as it gets loose. Now, what do you do????? Ignition kill....old school switch on servo, or channel operated relay, or Opti-kill. FOOLPROOF.

Also, a remote way to kill the motor...choke, ign kill, ....etc.....is required at a lot of events. Just good common sense.

THe whole debate of nylon / metal gears on throttle servos is old...use what makes you comfortable from your own experiences.

I have used HS5245mg and 225HB's, S148, 9001's, none ever really gave me problems but one....a JR 810 Heli tail servo....lightning fast and NO Torque.....bad, bad bad....it torched on me, when the linkage was rubbing after a rebuild. My bad.

Speed on the thrott is invaluable....a standard Fatuba will have you waiting for spool up...and that is bad at certain times in the flight envelope. ...;););)

Kevin Greene 07-14-2007 09:01 AM

RE: Let's try again DL-50
 
I gotta stay away from those Fatuba servos!!!!!:D:D:D

Kevin

dammud 07-15-2007 07:38 PM

RE: Let's try again DL-50
 
Speaking of engine spool-up... I've always wondered about the importance of this after seeing a turbine powered model
hovering and actually touching the rudder to the grass before climbing out (and this is part of a standard show routine.)
Those turbine engines take a LONG time to spool up!

Ken

3d-aholic 07-15-2007 08:05 PM

RE: Let's try again DL-50
 


ORIGINAL: jrjohn

I was just reading a couple days ago about a guy that flipped his choke by accident on final and crashed. I don't use a choke servo, too much extra weight and one more weak link in my opinion. This is America so please, do as you wish.

John
There are a lot of switches on my radio that if I just flip or move in an incorrect fashion will crash the plane....
A choke servo or lack thereof is not going to save you from yourself....

remcl1 07-15-2007 08:51 PM

RE: Let's try again DL-50
 


ORIGINAL: dammud

Speaking of engine spool-up... I've always wondered about the importance of this after seeing a turbine powered model
hovering and actually touching the rudder to the grass before climbing out (and this is part of a standard show routine.)
Those turbine engines take a LONG time to spool up!

Ken
Engine spool up is very important in 3d flying. Last year before Top Gun Quique brought his turbine powered plane here for a demo. It was definitely a handful due to the lake of decent spool up. Turbine powered 3d machines are not on the horizon. Good spool up is not only accelerating out of hover like a rocket. I rarely find the need for that. There is more need in 3d flying for a quick short blast of air over the surfaces. When you need this quick short blast it may be too late if you have to wait 2 seconds for it.

blw 07-15-2007 09:08 PM

RE: Let's try again DL-50
 
There was an interview with QQ right after he demonstrated his turboprop and he said that spool up lag was neglible above a certain N1 speed. I think it was something like 55%. His main problem with his turboprop was fuel consumption. He said that he only had about 7 minutes flight time on that plane. Also, he said that better turbines were on the horizon as well as a variable pitch prop which he rated as the number one improvement that was needed. Very interesting stuff.

BIGRCR 07-16-2007 06:47 AM

RE: Let's try again DL-50
 
The ignition switch will work as a very effective kill switch, just bend down and flip it off (also recognized by AMA and IMAA at an event).

John Garst-BIGRCR

Bob Pastorello 07-16-2007 06:57 AM

RE: Let's try again DL-50
 
Not if you're in the air....:eek:

3d-aholic 07-16-2007 09:19 AM

RE: Let's try again DL-50
 
I think I'm going to end up getting a kill switch for my plane. I don't want the added weight of a choke servo. Thing is these motors have a greater tendency to go through throttle servos than any other servo especially if they are in the motor box. I think the choke servo is still not a positive enough insurance policy. Also, it would be nice to positively know that if the radio goes out or runs out of battery, the motor will still be shut off as it plummets to the ground.

These planes will positively kill you if they hit just about any part of the human body at throttle except maybe the legs. So I'm not really getting mine for convenience just one time catastrophy insurance payment.

Bob Pastorello 07-16-2007 09:42 AM

RE: Let's try again DL-50
 
BTW - last outing with the DL on my GP Cap found me getting a little crazy with "gyroscopic" maneuvers, twisting around the prop with rudder and all sorts of bizarre attitudes. Cool looking stuff, lots of fun. Engine worked perfectly through all this, proving the three-line tank system and ceramic klunk works for me.

Also stressed the engine mounts, and they held up just fine. How did I stress them?
Well - the STOCK p.o.s. spinner from the Cap has a very short lip inside the lightened backplate. Yep. I had drilled the stock backplate for the DL, working fine, until I over-tightened. Yep. Bent the snot outta that thing, but didn't notice anything weird.

Until the flight with all the gyro and power stuff....after I landed, taxied up, saw the whole front end of the airplane shaking around like it had palsy. Scared the beeegesssus outta me. Shut it down, quickly diagnosed the problem, removed spinner, and flew more.

Post session - removed the cowl and really inspected everything. Firewall bolts hadn't even loosened up, and the alum. extrusion standoffs were perfect. No stress signs that I could see.

Meaning that most of the stress was on ME, and not the engine....

Yah, I know --- "If you'd had a good spinner to start with..... " :eek::eek:

chuck l 07-16-2007 04:23 PM

RE: Let's try again DL-50
 
Just an update:
The winds died enough today to fly, and the engine ran better, but not great. A lot of ratty sound over a wide range of engine speeds above idle and below full throttle. I removed the cowl and tweaked the carb on a good test stand. The ratty sound cleared right up with a little leaning of the low speed, yet the transition was good. A little more leaning and the transition went south, so I found the sweet spot and am much happier. (The high speed was also readjusted.) Couldn't fly the plane afterwards because of increasing winds, so I ran the engine for another half hour. I then switched to synthetic at 50:1 and re-tweaked the carb. I should be able to fly it tomorrow and expect nothing but excellent performance, ie we still haven't found a bad DL50.

Question, this is my first rear mounted carb so what do you guys do about the blow back fuel getting on the firewall? I just drilled a hole as the manual said, but didn't treat the wood. Dumb me, but what should I do now?

************************************************** ************************************************** ***********************************
HELP!!! I couldn't get my DL50 running right today, it wouldn't stay tuned. Read the notes below, then the description of the problem.

1. The engine has about 3 hours on it all with Lawn Boy Ashless at 30:1.
2. It flew "ok" last week on its first two flights in a new Hangar 9 Cap 232g. It had some mid range roughness. ProZinger 22x10, 6200rpm.
3. Since the first flight the vent for the metering diaphragm was added as Aerobob described earlier and the prop was switched to a ProZinger 22x8, 6800rpm The engine was retuned with cowl off. Ran excellent, no hesitation from idle to full throttle.

Today, it didn't run as well as it did after retuning with the 22x8 prop. It had the mid range roughness and didn't seem very strong although the plane had reasonable vertical. With the plane back on the ground, the engine would die when going to full throttle unless the throttle was advanced real slow. I removed the cowl and retuned the engine getting more high end rpm and a good transition. With the cowl back on, it ran the good. Refueled, flew the plane and it barely got off the ground for lack of power. Back on the ground, it ran just as bad as it did in the air. I did the removing the cowl, retuning, and trying to fly it, same thing, the engine ran badly. The plane has sat for three hours since getting home, and it ran just as badly as when I left the field. After the first retuning today, the high end needed to be richened for max rpm, by the last retuning the high end was turned in 180 degrees toward lean to get max rpm.

I don't think I'm having an overheating problem, and the engine seems to run the same with the cowl on or off, but I've attached pictures. This is my sixth gas engine and have never experience this problem before. Any suggestions would be greatly appreciated.

Chuck

3d-aholic 07-16-2007 04:32 PM

RE: Let's try again DL-50
 
Sounds lean if it won't transition from idle. And going going from a prop like the ProZinger to any other prop is like going from no load to a sudden engine load. Richen the low end up.

paul5992 07-16-2007 07:53 PM

RE: Let's try again DL-50
 
I have been thinking about ordering a dl from bob and after talking with aerobob and reading these posts it sounds like a good motor but if i have to cut a hole in the firewall to let the carb breath what do you do about fuel blowback into the plane. My plane has foam sheeting in it and any gas will disolve it. Anyone have a fix for this and maybe some pics of how you did it.

Bob Pastorello 07-16-2007 07:58 PM

RE: Let's try again DL-50
 
I've been watching for any of that. I've had the cowling off my Cap at least three times in the couple hours run time I've had. Honestly, there isn't any residue back there. SMALL oil film, very slight on the carb-side of the bottom standoff legs. VERY little on the throttle pushrod and throttle servo, which is almost directly behind the carb at "F1".

It may be an issue, but right now it's a "watch" thing. If some kind of problem arises, I'll figure out a way to seal off F1. that will at least contain anything to the inside of the motor box.


All times are GMT -8. The time now is 08:58 PM.


Copyright © 2022 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.