Notices
Glow Engines Discuss RC glow engines

Everything Radial Engines

Old 07-01-2016, 09:24 AM
  #3726  
cymaz
 
cymaz's Avatar
 
Join Date: Aug 2007
Location: UK
Posts: 718
Likes: 0
Received 2 Likes on 2 Posts
Default

Moki 180....it sounds nicer
Old 07-02-2016, 07:40 AM
  #3727  
AC2
My Feedback: (34)
 
Join Date: Dec 2001
Location: Modesto, CA
Posts: 446
Likes: 0
Received 0 Likes on 0 Posts
Default

Going Moki since it fits better but I really like the look of 7cyl. Sound is a plus but having to baffle the engine really turns me off
Old 07-07-2016, 06:28 PM
  #3728  
Pretendpilot
Junior Member
 
Join Date: Jun 2015
Posts: 23
Likes: 0
Received 0 Likes on 0 Posts
Default

some interesting reading regarding fuels...
http://www.smokemup.com/tech/fuels.php
Old 07-07-2016, 06:36 PM
  #3729  
jymster
My Feedback: (9)
 
jymster's Avatar
 
Join Date: Mar 2004
Location: Sydney, AUSTRALIA
Posts: 345
Received 0 Likes on 0 Posts
Default

Originally Posted by AC2
Going Moki since it fits better but I really like the look of 7cyl. Sound is a plus but having to baffle the engine really turns me off
You still have to baffle the Moki, so no difference there. The Evo radials run a lot cooler than the Mokis from my experience.
Old 07-11-2016, 01:19 PM
  #3730  
Radial power
 
Join Date: Jun 2006
Location: Reggio Emilia, ITALY
Posts: 107
Likes: 0
Received 0 Likes on 0 Posts
Default

Hello everybody,

I thought I'd share some information and experience that I got in the last few weeks.

Due to my negligence (no after run after the last run, about a year ago ), my OS FR5-300 began rusting. Specifically the crankshaft counterweight, the left-handed screw at the end of the crankshaft pin, the 4 slave rod pins and the races of the rear main bearing were showing signs of rust (after disassembly it was evident that in addition to these, each cam ring showed 2 "lines" of light rust stranding a clean path that the cam followers ran on). The engine still felt very smooth, and had it not been for the bearings I would have probably left it as is, but rust on the bearing races is no good, so I decided to change them. And clean out what I could while I was at it.

I referenced to the ASP-400 thread for the bearing sizes, but I found out that there's one difference: the ASP-400 uses 4x11x4 (ID x OD x width) bearings for the cam reduction shaft, while the OS FR5-300 uses 4x10x4 bearings. That was fairly evident when I compared the 4x11x4 bearings that I bought with the ones still installed in the engine. Classic DOH moment

This is what I ended up using:

- crankshaft front : 1 x SKF 6000ZTN9 (single-shielded (the Z suffix) with plastic retainer (the TN9 suffix). The original is an NTN 6000Z, single shielded with metal retainer)
- crankshaft rear : 1 x SKF 16003 (open, metal retainer. The original is NTN brand, otherwise identical)
- camshaft reduction gear : 2 x 4x10x4mm (ID x OD x width. I don't have a specific model number, as nothing's written on these tiny bearings)
- camshaft : 1 x 12x16x13 (needle bearing)
- master Rod : 1 x INA HK1012-B (needle bearing with outer race) (I didn't change this, but the original bearing clearly showed the "HK1012" indication on it)

All ball bearings I used are CN clearance, as I don't think that C3 clearance would be needed or beneficial for such a slow-turning engine. None of the bearings I removed indicated anything as far as clearance is concerned, so I assume that they were CN as well.

I couldn't find proper E-clips for the link pins at a local hardware shop. They did have 4mm E-clips, but comparing them with the ones still installed in the engine, the new ones looked significantly smaller. As I didn't want to take a chance I decided non to use them, and so I couldn't remove the stock E-clips, as removing and reusing an E-clip is a no-no. Therefore I couldn't remove the master rod (to replace the main rod bearing) or clean the link pins. I'm not worried about this, as the main rod bearing still looked and felt ok, and the rusted parts only showed rust on the exposed areas, so the critical load-bearing surfaces should be ok.

I had problems getting 2 bearings out: the big 16003 rear bearing (that was REAL tight) and, obviously, the small front cam bearing. The rear bearing came out after heating the plate it's installed in and then tapping on the bearing with a plastic mallet.
The small cam bearing was another matter: I tried to file the side of a screw to use as a puller to pull it out, no go. I tried heat, no go. I tried to use wax to press it out, no go (I actually damaged the bearing using wax, dislodging one of the shields, part of the cage and damaging the other shield).
In the end I had to build an inside puller using an M3 socket head countersunk screw. Basically I filed away most of the head, leaving a "foot" on one side of the head just large enough to slide inside the bearing and under it, leaving the threaded portion of the screw sticking up. Then I used a piece of wire to "fill up" the space between the inner bearing race and the screw. Then I placed a big washer directly over the bearing, resting on top of the nose cone "ribs" containing the cam followers, a smaller washer on top of the big washer and then a nut threaded into the screw. Then started turning, and after a few turns the bearing began to move.

The other bearings were easy: the front bearing came out with a light tap without needing to heat up the nose cone, same with the other cam bearing. The cam drum needle bearing fell out under its own weight!

I cleaned the parts with a soft brass brush and some denaturated alcohool, but I didn't want to risk ruining the "working" surfaces (such as the crank pin), even though they showed some stains. So I decided to only do a light cleaning, removing just the evident rust. As a result the some parts remained somewhat dark or "spotted", but I suppose that's fine.

Setting the timing was not hard, just line up the dots. When the nose cone is back together, double and triple check that the big hole in the reduction gear lines up with the holes in the bottom part of the center plate while the crankshaft is at simmetrical positions to the center. That's a very good indication that the first mesh (crankshaft to gear reduction shaft) is correct. For the second mesh (reduction shaft to cam drum), place two screws where the pushrods for cylinder 1 would be, lightly press on them with your fingers and slowly rotate the crankshaft past TDC for cylinder 1. If the screws don't move, rotate the shaft one full turn. If they do move, make sure that they are both halfway raised with the shaft at TDC.
In case anyone's interested, the gears on the reduction shaft have 58 and 22 teeth. I didn't count the teeth on the crankshaft or the cam drum gear, but I suspect that they are respectively 29 and 66 teeth each. That would give a 2:1 reduction for the first step and 3:1 for the second step, for a combined reduction ratio of 6:1. This means that if the second mesh os off by one tooth, then it means that the cam drum is off by 360/66 = 5.45. By applying the total reduction ratio in reverse we get that the crankshaft would be off by 5.45 x 6 = 32.72 That should be fairly evident to check with the two screws on top of the cam followers.

Last saturday I re-ran the engine on the bench and got 7200 rpm with a 20x8 Menz-S propeller (saw a few peaks at 7400rpm, just after quickly advancing the throttle, then the rpm fell back down by 100 - 200 rpm). I think I could have pushed it a little further, as I could see a slight rpm drop when advancing the throttle in the very last part of its travel. Also I lost a cylinder a couple of times at or near full throttle, so I suspect that I was still a little rich. Also, turning on glow heat near full throttle increased the rpm, so I think that the plugs were not as hot at they should have been, again possibly a symptom of a rich mixture.
I still couldn't get a decent idle, probably a combination of a not-yet-correct fuel mixture and a weak-ish glow ignition system. Anything under 2000 rpm is unstable. Probably after some more run time and after the high speed needle is set, then the low speed will be easier to set as well. And as far as the weak glow goes, I'll upgrade the test stand with better glow plug connectors, heavier gauge wires and lower-value dropper resistors.

I can tell you, though, that while I was experimenting with the idle, chopping the throttle with a very lean low end mixture produced some nice exhaust pops. Often multiple pops per chop

After the run, I drained the oil that was inside the engine, FLOODED it with mineral oil (I think that's the correct english name?) and then stored in a place that should be less humid than the garage it was before. Let's see if that helps.

If anyone is interested I can post some photos of the teardown and reassembly. Maybe not all of them, as they're 291MB total

Andrea.
Old 08-16-2016, 01:17 PM
  #3731  
Jim.Thompson
 
Jim.Thompson's Avatar
 
Join Date: Sep 2015
Location: Bellingen NSW Australia
Posts: 332
Likes: 0
Received 0 Likes on 0 Posts
Default

I have just discovered this thread and I am new to radial engines. In fact, new to powered aircraft as I fly mostly gliders.
However, I have just build a 30% scale Klemm Kl25 model for towing purposed and have found that the 99 cc single cylinder Stihl engine that I converted is creating far too much vibration for safety of the aircraft servos and control linkages. Build thread here: http://www.rcgroups.com/forums/showthread.php?t=2523079
As a result of this conclusion, I have started to consider alternative power plants. A radial engine seems a logical conclusion.
The weight of my Klemm with the Stihl engine and home made steel muffler is around 22 kg.

Is a Moki 150 radial likely to be a suitable power plant for this aircraft? Also, what other available engines might suit? I particularly want a petrol/gas engine, as I want to use conveniently available fuel. And I would prefer a low oil content ratio for obvious reasons. Four stroke if possible.
Apologies for the basic questions; as I say, new to this field of modelling.

I will post a couple of pics of my new Klemm.
Attached Thumbnails Click image for larger version

Name:	full assembly 3.JPG
Views:	68
Size:	749.8 KB
ID:	2177206   Click image for larger version

Name:	Full assembly.JPG
Views:	65
Size:	533.7 KB
ID:	2177207  
Old 08-16-2016, 01:30 PM
  #3732  
chorner
 
Join Date: Aug 2014
Posts: 397
Received 2 Likes on 2 Posts
Default

Originally Posted by Radial power
Hello everybody,

I thought I'd share some information and experience that I got in the last few weeks.

Due to my negligence (no after run after the last run, about a year ago ), my OS FR5-300 began rusting. Specifically the crankshaft counterweight, the left-handed screw at the end of the crankshaft pin, the 4 slave rod pins and the races of the rear main bearing were showing signs of rust (after disassembly it was evident that in addition to these, each cam ring showed 2 "lines" of light rust stranding a clean path that the cam followers ran on). The engine still felt very smooth, and had it not been for the bearings I would have probably left it as is, but rust on the bearing races is no good, so I decided to change them. And clean out what I could while I was at it.

I referenced to the ASP-400 thread for the bearing sizes, but I found out that there's one difference: the ASP-400 uses 4x11x4 (ID x OD x width) bearings for the cam reduction shaft, while the OS FR5-300 uses 4x10x4 bearings. That was fairly evident when I compared the 4x11x4 bearings that I bought with the ones still installed in the engine. Classic DOH moment

This is what I ended up using:

- crankshaft front : 1 x SKF 6000ZTN9 (single-shielded (the Z suffix) with plastic retainer (the TN9 suffix). The original is an NTN 6000Z, single shielded with metal retainer)
- crankshaft rear : 1 x SKF 16003 (open, metal retainer. The original is NTN brand, otherwise identical)
- camshaft reduction gear : 2 x 4x10x4mm (ID x OD x width. I don't have a specific model number, as nothing's written on these tiny bearings)
- camshaft : 1 x 12x16x13 (needle bearing)
- master Rod : 1 x INA HK1012-B (needle bearing with outer race) (I didn't change this, but the original bearing clearly showed the "HK1012" indication on it)

All ball bearings I used are CN clearance, as I don't think that C3 clearance would be needed or beneficial for such a slow-turning engine. None of the bearings I removed indicated anything as far as clearance is concerned, so I assume that they were CN as well.

I couldn't find proper E-clips for the link pins at a local hardware shop. They did have 4mm E-clips, but comparing them with the ones still installed in the engine, the new ones looked significantly smaller. As I didn't want to take a chance I decided non to use them, and so I couldn't remove the stock E-clips, as removing and reusing an E-clip is a no-no. Therefore I couldn't remove the master rod (to replace the main rod bearing) or clean the link pins. I'm not worried about this, as the main rod bearing still looked and felt ok, and the rusted parts only showed rust on the exposed areas, so the critical load-bearing surfaces should be ok.

I had problems getting 2 bearings out: the big 16003 rear bearing (that was REAL tight) and, obviously, the small front cam bearing. The rear bearing came out after heating the plate it's installed in and then tapping on the bearing with a plastic mallet.
The small cam bearing was another matter: I tried to file the side of a screw to use as a puller to pull it out, no go. I tried heat, no go. I tried to use wax to press it out, no go (I actually damaged the bearing using wax, dislodging one of the shields, part of the cage and damaging the other shield).
In the end I had to build an inside puller using an M3 socket head countersunk screw. Basically I filed away most of the head, leaving a "foot" on one side of the head just large enough to slide inside the bearing and under it, leaving the threaded portion of the screw sticking up. Then I used a piece of wire to "fill up" the space between the inner bearing race and the screw. Then I placed a big washer directly over the bearing, resting on top of the nose cone "ribs" containing the cam followers, a smaller washer on top of the big washer and then a nut threaded into the screw. Then started turning, and after a few turns the bearing began to move.

The other bearings were easy: the front bearing came out with a light tap without needing to heat up the nose cone, same with the other cam bearing. The cam drum needle bearing fell out under its own weight!

I cleaned the parts with a soft brass brush and some denaturated alcohool, but I didn't want to risk ruining the "working" surfaces (such as the crank pin), even though they showed some stains. So I decided to only do a light cleaning, removing just the evident rust. As a result the some parts remained somewhat dark or "spotted", but I suppose that's fine.

Setting the timing was not hard, just line up the dots. When the nose cone is back together, double and triple check that the big hole in the reduction gear lines up with the holes in the bottom part of the center plate while the crankshaft is at simmetrical positions to the center. That's a very good indication that the first mesh (crankshaft to gear reduction shaft) is correct. For the second mesh (reduction shaft to cam drum), place two screws where the pushrods for cylinder 1 would be, lightly press on them with your fingers and slowly rotate the crankshaft past TDC for cylinder 1. If the screws don't move, rotate the shaft one full turn. If they do move, make sure that they are both halfway raised with the shaft at TDC.
In case anyone's interested, the gears on the reduction shaft have 58 and 22 teeth. I didn't count the teeth on the crankshaft or the cam drum gear, but I suspect that they are respectively 29 and 66 teeth each. That would give a 2:1 reduction for the first step and 3:1 for the second step, for a combined reduction ratio of 6:1. This means that if the second mesh os off by one tooth, then it means that the cam drum is off by 360/66 = 5.45. By applying the total reduction ratio in reverse we get that the crankshaft would be off by 5.45 x 6 = 32.72 That should be fairly evident to check with the two screws on top of the cam followers.

Last saturday I re-ran the engine on the bench and got 7200 rpm with a 20x8 Menz-S propeller (saw a few peaks at 7400rpm, just after quickly advancing the throttle, then the rpm fell back down by 100 - 200 rpm). I think I could have pushed it a little further, as I could see a slight rpm drop when advancing the throttle in the very last part of its travel. Also I lost a cylinder a couple of times at or near full throttle, so I suspect that I was still a little rich. Also, turning on glow heat near full throttle increased the rpm, so I think that the plugs were not as hot at they should have been, again possibly a symptom of a rich mixture.
I still couldn't get a decent idle, probably a combination of a not-yet-correct fuel mixture and a weak-ish glow ignition system. Anything under 2000 rpm is unstable. Probably after some more run time and after the high speed needle is set, then the low speed will be easier to set as well. And as far as the weak glow goes, I'll upgrade the test stand with better glow plug connectors, heavier gauge wires and lower-value dropper resistors.

I can tell you, though, that while I was experimenting with the idle, chopping the throttle with a very lean low end mixture produced some nice exhaust pops. Often multiple pops per chop

After the run, I drained the oil that was inside the engine, FLOODED it with mineral oil (I think that's the correct english name?) and then stored in a place that should be less humid than the garage it was before. Let's see if that helps.

If anyone is interested I can post some photos of the teardown and reassembly. Maybe not all of them, as they're 291MB total

Andrea.
Andrea,

For the E-clips just order these:
http://www3.towerhobbies.com/cgi-bin...?&I=LXACVL&P=Z (same ones used on the FR5 as the FR7)

I also did a complete rebuild with new bearings, converted the engine to CDI, and used all OS parts on what was possible to swap. A lot of OS parts, and it runs way smoother now. After break-in I am seeing 8,350rpm on a 20x8 Mejzlik prop. Much higher than your 7,200 you're seeing And check out this idle; posted a video up on YouTube:

https://www.youtube.com/watch?v=_pgrw3svLPc
Old 08-16-2016, 03:46 PM
  #3733  
ya33a
 
Join Date: Feb 2005
Location: Wodonga, AUSTRALIA
Posts: 188
Likes: 0
Received 0 Likes on 0 Posts
Default

Good Morning,

Wow, looks good for a tug, a moki would be a beast on that, have you considered anti vibration mounts from DA in Mansfield QLD? Or give them a call as they had some 1/3 scale Extras running 200cc twins putting out some serious power and didn't seem to have too many issues with vibration. Just a suggestion that may keep your bird flying as it is... Although the Moki would look really good and sound awesome - you may not fly the glider with it....
Old 08-16-2016, 05:46 PM
  #3734  
LarsL
 
Join Date: Sep 2006
Location: Shorewood, WI
Posts: 195
Likes: 0
Received 0 Likes on 0 Posts
Default

Jim,

While the Moki would sound great, I think that a DA-150, or DA-170 would be a better choice. While not a 4-stroke, either would be low on vibration (opposed twins), would have great power, and would be more economical (price & fuel economy) than the Moki.

Thanks,
Lars
Old 08-16-2016, 08:48 PM
  #3735  
Jim.Thompson
 
Jim.Thompson's Avatar
 
Join Date: Sep 2015
Location: Bellingen NSW Australia
Posts: 332
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks for the feedback and suggestions ya and Lars!
I will do some research on DA engines you suggest.
Old 08-18-2016, 09:08 AM
  #3736  
Joespeeder
 
Join Date: Dec 2007
Location: Davison, MI
Posts: 548
Likes: 0
Received 0 Likes on 0 Posts
Default

Hey Jim,

Look at these... Not radials, but still lots of cool sounding options !


http://www.valachmotors.com/motory.html


http://www.valachmotors.com/vm140b2/vm140b2.html

https://www.youtube.com/watch?v=OjDq3WxQD-4

http://www.valachmotors.com/vm170b2/vm170b2.html

https://www.youtube.com/watch?v=LLNqwwVbLPk


http://www.rotoengines.com/Four-stro...nes-c2_0_1.htm



http://www.rotoengines.com/ROTO-170-...engine-d37.htm

https://www.youtube.com/watch?v=sMjqDffO-1s




Joe
Old 08-18-2016, 05:19 PM
  #3737  
Jim.Thompson
 
Jim.Thompson's Avatar
 
Join Date: Sep 2015
Location: Bellingen NSW Australia
Posts: 332
Likes: 0
Received 0 Likes on 0 Posts
Default

Thanks Joe,
They look really nice. However, I am a bit put off by the high oil to fuel ration required. I would fancy something a bit cleaner burning.
Old 08-18-2016, 05:25 PM
  #3738  
Jim.Thompson
 
Jim.Thompson's Avatar
 
Join Date: Sep 2015
Location: Bellingen NSW Australia
Posts: 332
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by ya33a
............................................, have you considered anti vibration mounts from DA in Mansfield QLD? .............................................
I have only just absorbed that point in your post ya! After reading it for the second time.
I will give them a call today. Thanks for the tip.

Jim.

p.s. satellite internet connection down. Might not be able to answer any messages until it is restored.

Last edited by Jim.Thompson; 08-19-2016 at 11:03 AM.
Old 08-18-2016, 11:23 PM
  #3739  
ya33a
 
Join Date: Feb 2005
Location: Wodonga, AUSTRALIA
Posts: 188
Likes: 0
Received 0 Likes on 0 Posts
Default

Hi Jim,
Yes DA - Desert Aircraft are or were in Mansfield just off the gateway Rd near Bunnings. They have a great selection of everything imaginable for giant aircraft. And are really helpful. The guys fly at Tingalpa and down at Logan...
Old 08-19-2016, 11:05 AM
  #3740  
Jim.Thompson
 
Jim.Thompson's Avatar
 
Join Date: Sep 2015
Location: Bellingen NSW Australia
Posts: 332
Likes: 0
Received 0 Likes on 0 Posts
Default

Desert Aircraft advise that they no longer stock the anti-vibration mounts. They formed the conclusion that they are no good and sometimes even exacerbate the problem.
Old 08-19-2016, 10:23 PM
  #3741  
the pope
Senior Member
 
Join Date: Apr 2005
Location: goolwasa, AUSTRALIA
Posts: 1,680
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by ya33a
Hi Jim,
Yes DA - Desert Aircraft are or were in Mansfield just off the gateway Rd near Bunnings. They have a great selection of everything imaginable for giant aircraft. And are really helpful. The guys fly at Tingalpa and down at Logan...
I can vouch for their helpfulness , Ive been annoying Mark for quite awhile on a little 120mm quad and he's kept his cool and always responded to my emails . Ive really felt for him . Cheers
Old 08-20-2016, 01:33 AM
  #3742  
ya33a
 
Join Date: Feb 2005
Location: Wodonga, AUSTRALIA
Posts: 188
Likes: 0
Received 0 Likes on 0 Posts
Default

Hi Jim,

Ok, then there are a few other things to try, the first is to reposition the prop so it is 90 degrees out of where you would normally have it positioned ie at the 6 O'Clock position instead of the 3 O'Clock for a hand start, that may help to dampen the vibes, then brace the internals with cross pieces of balsa, ply etc, also repositioning the motor on the fuse so it's mounted sidewinder style instead of up and down can sometimes help. I can see how the isolation mounts could cause issues if the nylon/neoprene wears then the vibes are untamed and it would start to flog the mounts out even more. Changing the prop to a different pitch / diameter to change the characteristics of the engine can also help... different 'Sweet spot' and less time the engine spends in the harmonic region. To explain the issues with vibration, I drove a 1992 Falcon and at 94KMH it would start to build up a harmonic vibration that I could get to shake the rear-vision mirror so badly it couldn't be used and fell off the windscreen once. The Ford Dealer replaced the tyres twice and gave the car a wheel alignment and balance 4 times, it didn't make much difference.... So I just drove at 105 on the highway - smooth as silk...Above 98 and at 90 or below...
Old 08-20-2016, 08:08 AM
  #3743  
Radial power
 
Join Date: Jun 2006
Location: Reggio Emilia, ITALY
Posts: 107
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by chorner
Andrea,

For the E-clips just order these:
http://www3.towerhobbies.com/cgi-bin...?&I=LXACVL&P=Z (same ones used on the FR5 as the FR7)

I also did a complete rebuild with new bearings, converted the engine to CDI, and used all OS parts on what was possible to swap. A lot of OS parts, and it runs way smoother now. After break-in I am seeing 8,350rpm on a 20x8 Mejzlik prop. Much higher than your 7,200 you're seeing And check out this idle; posted a video up on YouTube:

https://www.youtube.com/watch?v=_pgrw3svLPc
I ordered the e-clips for the FR5-300 (http://www3.towerhobbies.com/cgi-bin...01p??&I=LXCP06), but they are on back order and they haven't been shipped yet (ordered on 07/07/2016). Since I knew that it would take a long time to get these from Tower, I tried to source some e-clips locally, with the results that I mentioned. Honestly, I didnl't think about using the parts from the FR7. That's a good idea actually, even though in my case it's too late as I have already ordered the FR5 e-clips.

As for your results, they are certainly great, but I'm not sure they're directly comparable with my reading: your engine is 15cc larger and it has spark ignition; my engine is not fully broken in and not fully leaned out for max RPM in that 7200rpm reading (as I wrote in my previous post). In addition, as far as I understand, the Mejzlik propellers seem to turn higher rpm numbers than the Menz S. I haven't tried a Mejzlik prop on my engine though, so I cannot be sure.
I may take into consideration converting my radial to spark ignition at a later time, but for now it will remain with glow ignition.
Old 08-20-2016, 08:26 AM
  #3744  
AC2
My Feedback: (34)
 
Join Date: Dec 2001
Location: Modesto, CA
Posts: 446
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Jim.Thompson
Thanks Joe,
They look really nice. However, I am a bit put off by the high oil to fuel ration required. I would fancy something a bit cleaner burning.
Jim
Would you mind elaborating a bit more on the ratio please...
Old 08-20-2016, 12:15 PM
  #3745  
Jim.Thompson
 
Jim.Thompson's Avatar
 
Join Date: Sep 2015
Location: Bellingen NSW Australia
Posts: 332
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by AC2
Jim
Would you mind elaborating a bit more on the ratio please...
Recommended: 25 :1 --33: 1
See post #3736 above.
Old 08-20-2016, 01:53 PM
  #3746  
chorner
 
Join Date: Aug 2014
Posts: 397
Received 2 Likes on 2 Posts
Default

Originally Posted by Radial power
I ordered the e-clips for the FR5-300 (http://www3.towerhobbies.com/cgi-bin...01p??&I=LXCP06), but they are on back order and they haven't been shipped yet (ordered on 07/07/2016). Since I knew that it would take a long time to get these from Tower, I tried to source some e-clips locally, with the results that I mentioned. Honestly, I didnl't think about using the parts from the FR7. That's a good idea actually, even though in my case it's too late as I have already ordered the FR5 e-clips.

As for your results, they are certainly great, but I'm not sure they're directly comparable with my reading: your engine is 15cc larger and it has spark ignition; my engine is not fully broken in and not fully leaned out for max RPM in that 7200rpm reading (as I wrote in my previous post). In addition, as far as I understand, the Mejzlik propellers seem to turn higher rpm numbers than the Menz S. I haven't tried a Mejzlik prop on my engine though, so I cannot be sure.
I may take into consideration converting my radial to spark ignition at a later time, but for now it will remain with glow ignition.
Oops, I didn't realize you had the OS FR5-300. For some reason I assumed you had the ASP. Very nice! I bet you'd be within striking distance to this ASP in performance on spark, with smaller capacity. The OS is a much smoother and better made engine as a whole; still some weak spots like the valve seats on this ASP, even with all the OS parts.
Old 08-20-2016, 01:55 PM
  #3747  
Joespeeder
 
Join Date: Dec 2007
Location: Davison, MI
Posts: 548
Likes: 0
Received 0 Likes on 0 Posts
Default

Hey Jim,

The Roto engines are 40:1.

Joe
Old 08-20-2016, 02:09 PM
  #3748  
Jim.Thompson
 
Jim.Thompson's Avatar
 
Join Date: Sep 2015
Location: Bellingen NSW Australia
Posts: 332
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by Joespeeder
Hey Jim,

The Roto engines are 40:1.

Joe
That's some degree better. I have yet to look at them.
While I am convinced that a boxer configuration twin cylinder engine is likely the most suitable for my newly built Klemm, I am still researching radial options. To be honest, I cannot afford one but the romantic side of me attracts me to one. You may be aware of the 50% Klemm that is powered by a 420 cc radial. Several youtube videos up of it flying. Impressive sound and good power for towing. My Klemm is also intended to be a tug plane. Gliders being my #1 flying interest.

Last edited by Jim.Thompson; 08-20-2016 at 02:11 PM.
Old 08-30-2016, 06:58 AM
  #3749  
airraptor
My Feedback: (66)
 
Join Date: Jan 2004
Location: fairfield, CA
Posts: 4,191
Likes: 0
Received 4 Likes on 4 Posts
Default

Hello, I just picked up an old OS FR-5 300 and with out reading every page and all is there any mods to the OS FR 5 to make all cylinders run equally? Can I adapt the rotor from the FR-7?
Old 10-04-2016, 06:06 AM
  #3750  
Maxam
My Feedback: (62)
 
Join Date: Jul 2005
Location: Indianapolis, IN
Posts: 1,146
Received 10 Likes on 10 Posts
Default

Airraptor, You cannot adapt the distribution unit from the FR7 due to 7 mounting points rather than 5 on your engine. I just picked up an FR7 and after a bit of work, I got it to run well. It's supplied carb is not very good. I made an adapter so the pegasus 240/320 carb could be used resulting in much better running. It is important to clean out the rocker box area.The bottom ones must be drained or they will fill up completely with oil. -Tom

Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.