breaking in a new motor
01-15-2011, 01:11 PM
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breaking in a new motor
i have a question i have a dm 55( dle 55 clone) i heard to differnt things with breaking it in one is use the prop i will be flying on aka a 23x8 or should i use what dle suguest a 22x8 to break it in this is my first new gas motor normaly i flew nitro powered planes any info will help
01-15-2011, 02:36 PM
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RE: breaking in a new motor
ok here is what im wondering my plane is a laser 200 1/4 scale make back in the 70's ( ya she is old) would a 22x8 be enought to fly it around or would the extra inch of prop be wiser to fly it on the plane weight is 18 lbs 6 oz 87inch wingspawn 68.75 fuse ya i know she heavy but back then the planes where madfe like tanks
01-15-2011, 02:59 PM
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RE: breaking in a new motor
A 1/4 scale Laser 200 has a wingspan of around 72", your engine is far too strong and heavy for this plane. Doesn't much matter which prop you put on it. Maybe you have the 1/3rd scale version?
01-15-2011, 03:03 PM
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RE: breaking in a new motor
maby lol i know it's 87 inch wing spawn i not sure what the scale is this is going off of planes with the same linth of wing here is a pic of the plane in my front room
01-15-2011, 03:11 PM
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RE: breaking in a new motor
im just trying to find out if the 22x8 would enought prop for this plane at it's weight i just dont want to lose my plane do to not enough prop aka not enough arse to get the plane airborn or over rmping the motor
01-15-2011, 03:47 PM
#8
RE: breaking in a new motor
!8 lbs.+ is nothing for a 30% airframe. If the DM55 turns a quality 22x8 prop at 7200+ RPM, which it should if it's worth anything, it'll pull at least 28 lbs. of thrust. Plenty for your Laser. Start with the 22x8 and see if you like it, no one can select the best prop for your flying style and airframe/engine combination except you.
01-15-2011, 04:40 PM
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RE: breaking in a new motor
thanks jody i has a vess 23b on it tell it accdently got broke lol never seen the air with it but i will try it i know i had a quadra q52 running a 20x8 and it flew the plane just it lacked power ty for your help agine
01-15-2011, 07:10 PM
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RE: breaking in a new motor
You want a lighter load for break in. Large props are a heavier load.
Large loads produce heat. Heat is the enemy of any engine. Heat on a NEW engine is a recipe for a short life span. You can't hurt a small 2-stroke like this with RPM's.... you could, but it would have to be something in the range of a 16" prop before you could wind it up enough to pop it.
The point is, you should be using a lighter load prop for beak in. RPM's in this range don't kill engines. HEAT kills engines. Large props make heat on parts that aren't mated and fitted up to each other yet. You gotta let that engine spin some RPM's and drink some fuel before all the parts inside will get all nice and cozy next to each other. Once the parts are all friends and cozied up to each other, there's less friction. Less friction means less heat.
THEN you can put a larger prop on it.
I'd recommend a 21x8 prop and 32:1 fuel mix for about 5 - 8 gallons. Then slap the 22-8 on it and lean it to 40:1 or 50:1 if you desire.
Or........
You could just take the friggin sledge hammer to it now and get it over with. Same result as putting a 23" prop on it, right outta the box.
Large loads produce heat. Heat is the enemy of any engine. Heat on a NEW engine is a recipe for a short life span. You can't hurt a small 2-stroke like this with RPM's.... you could, but it would have to be something in the range of a 16" prop before you could wind it up enough to pop it.
The point is, you should be using a lighter load prop for beak in. RPM's in this range don't kill engines. HEAT kills engines. Large props make heat on parts that aren't mated and fitted up to each other yet. You gotta let that engine spin some RPM's and drink some fuel before all the parts inside will get all nice and cozy next to each other. Once the parts are all friends and cozied up to each other, there's less friction. Less friction means less heat.
THEN you can put a larger prop on it.
I'd recommend a 21x8 prop and 32:1 fuel mix for about 5 - 8 gallons. Then slap the 22-8 on it and lean it to 40:1 or 50:1 if you desire.
Or........
You could just take the friggin sledge hammer to it now and get it over with. Same result as putting a 23" prop on it, right outta the box.
01-15-2011, 08:04 PM
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RE: breaking in a new motor
I'm going to flip that a little. Heat is a good thing when managed correctly. A 10 pitch prop is both more load and more speed. The 8 pitch will fly a little slower but with more pull. You're call here.
How you manage the throttle and cooling will determine what the engine can and will do. If you just slap a prop on and go for the gusto the engine will be rather short lived and never develop the power it could have. If you take things easy for a couple gallons of gas, never getting the engine too hot or letting it run to cool or cool too fast, things will be a lot better. Personally I'd run a 22 or 23-8 on the engine from the beginning but I would also tune the engine correctly and assure good heat management and cycling.
None of you break in an engine like I do because it's labor intensive and takes a lot of time. At least an hour and half with a very good cooling supply and live temp monitoring. However, all of you can perform a good break in if you do it in managed stages. Idle for 30 seconds, then 1/4 throttle for 15 or 20 seconds, then repeat the idle. Do that repeatedly while incrementally increasing the rpm a little at a time and things seat and cycle well. Hard to do that process in the air though. For an air break in just avoid full power for the first tank of gas, and don't do any extended uplines or 3d. Gentle aerobatics for two tanks minimum. No 3d for at least 4 tanks of gas. Once you go to full power don't hold it there. Short periods of high throttle with cool down periods in between the power runs. Do that for a gallon at least.
How you manage the throttle and cooling will determine what the engine can and will do. If you just slap a prop on and go for the gusto the engine will be rather short lived and never develop the power it could have. If you take things easy for a couple gallons of gas, never getting the engine too hot or letting it run to cool or cool too fast, things will be a lot better. Personally I'd run a 22 or 23-8 on the engine from the beginning but I would also tune the engine correctly and assure good heat management and cycling.
None of you break in an engine like I do because it's labor intensive and takes a lot of time. At least an hour and half with a very good cooling supply and live temp monitoring. However, all of you can perform a good break in if you do it in managed stages. Idle for 30 seconds, then 1/4 throttle for 15 or 20 seconds, then repeat the idle. Do that repeatedly while incrementally increasing the rpm a little at a time and things seat and cycle well. Hard to do that process in the air though. For an air break in just avoid full power for the first tank of gas, and don't do any extended uplines or 3d. Gentle aerobatics for two tanks minimum. No 3d for at least 4 tanks of gas. Once you go to full power don't hold it there. Short periods of high throttle with cool down periods in between the power runs. Do that for a gallon at least.
01-16-2011, 06:31 AM
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RE: breaking in a new motor
glad amy laser is not a 3d plane lol it's a IMACtype flyer so it will never see hard core 3D i am running a 32:1 mix and i try not to fly full throttle all the time so i will try the 22x8 and see what it does
01-16-2011, 09:49 AM
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RE: breaking in a new motor
trust me i will be taking it easy for a wile
the plane is old so i try to fly it with respect and i did not know that thanks for the info TOM
the plane is old so i try to fly it with respect and i did not know that thanks for the info TOM
01-16-2011, 12:33 PM
#18
RE: breaking in a new motor
ORIGINAL: Tired Old Man
I'm going to flip that a little. Heat is a good thing when managed correctly. A 10 pitch prop is both more load and more speed. The 8 pitch will fly a little slower but with more pull. You're call here.
How you manage the throttle and cooling will determine what the engine can and will do. If you just slap a prop on and go for the gusto the engine will be rather short lived and never develop the power it could have. If you take things easy for a couple gallons of gas, never getting the engine too hot or letting it run to cool or cool too fast, things will be a lot better. Personally I'd run a 22 or 23-8 on the engine from the beginning but I would also tune the engine correctly and assure good heat management and cycling.
None of you break in an engine like I do because it's labor intensive and takes a lot of time. At least an hour and half with a very good cooling supply and live temp monitoring. However, all of you can perform a good break in if you do it in managed stages. Idle for 30 seconds, then 1/4 throttle for 15 or 20 seconds, then repeat the idle. Do that repeatedly while incrementally increasing the rpm a little at a time and things seat and cycle well. Hard to do that process in the air though. For an air break in just avoid full power for the first tank of gas, and don't do any extended uplines or 3d. Gentle aerobatics for two tanks minimum. No 3d for at least 4 tanks of gas. Once you go to full power don't hold it there. Short periods of high throttle with cool down periods in between the power runs. Do that for a gallon at least.
I'm going to flip that a little. Heat is a good thing when managed correctly. A 10 pitch prop is both more load and more speed. The 8 pitch will fly a little slower but with more pull. You're call here.
How you manage the throttle and cooling will determine what the engine can and will do. If you just slap a prop on and go for the gusto the engine will be rather short lived and never develop the power it could have. If you take things easy for a couple gallons of gas, never getting the engine too hot or letting it run to cool or cool too fast, things will be a lot better. Personally I'd run a 22 or 23-8 on the engine from the beginning but I would also tune the engine correctly and assure good heat management and cycling.
None of you break in an engine like I do because it's labor intensive and takes a lot of time. At least an hour and half with a very good cooling supply and live temp monitoring. However, all of you can perform a good break in if you do it in managed stages. Idle for 30 seconds, then 1/4 throttle for 15 or 20 seconds, then repeat the idle. Do that repeatedly while incrementally increasing the rpm a little at a time and things seat and cycle well. Hard to do that process in the air though. For an air break in just avoid full power for the first tank of gas, and don't do any extended uplines or 3d. Gentle aerobatics for two tanks minimum. No 3d for at least 4 tanks of gas. Once you go to full power don't hold it there. Short periods of high throttle with cool down periods in between the power runs. Do that for a gallon at least.
please correct me if i am wrong, but are you saying you do the breakin on the bench?
sounds right, and with controlled temps it seems to be a good idea if for nothing else but to just get the engine somewhat dialed in before it's first flight.
thx
-mike
01-16-2011, 01:04 PM
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RE: breaking in a new motor
i do a lot of ground running do to the snow but thankfully my cowl has a lot of space for cooling here is a pic of it dont mind the mess lol i been hunting for some parts i had in a box not running on a bench but best i can do beings i have not built a bench yet
01-16-2011, 01:55 PM
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RE: breaking in a new motor
I prefer a super controlled environment for break in. Only an extreme few have that available. They might have a bench but they never, ever, have a suitable and adjustable cooling air supply. So that leaves them with an aerial break in, which when done reasonably well does a great job. A poorly executed bench break in can and does do more damage than good. A badly done aerial break in leaves one with the same results as a bad bench break in. Bad ring seals, low compression, lower than normal RPM, and a scored cylinder wall. It all comes down to self restraint, and a little understanding of what needs to be done for the best long term performance.
What must be understood is that numerous engines may need to be subjected to the break in process at the same time, so those have to be bench run to get the job done. If you have 10 or 20 engines that have to be broken in and tuned for shipment on the same day, and that process will be repeated over numerous days, the bench is the only way it can get done because you can do many at the same time if you are set up for it.
What must be understood is that numerous engines may need to be subjected to the break in process at the same time, so those have to be bench run to get the job done. If you have 10 or 20 engines that have to be broken in and tuned for shipment on the same day, and that process will be repeated over numerous days, the bench is the only way it can get done because you can do many at the same time if you are set up for it.
01-16-2011, 02:21 PM
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RE: breaking in a new motor
i dont run the motor for long lol 10 minets each time i know when doing a flying break in you hafto be nice to your motor and treat it with respect i awalys done that with my nitro motors and will do the same with gassers i have a flying buddy thats been flyiong gassers for 20 years he teaching me about how to break in the motors right so thanks for the info
01-16-2011, 05:18 PM
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RE: breaking in a new motor
i got it set allmost perfect i think if i try and lean it more the motor bogs aka not enough fuel so when it got to that point i turned the niddle 1/2 a turn back seems to be running fine will let ya know when i pick up the 22x8 prop tomarrow i was running a vess 23b tell it got broke betting i will hafto retune the motor hopping i dont tho