Author Topic: Discovery retro 60 (Read 8262 times)

big ron · « **on:** September 08, 2015, 01:37:05 PM »

Does anyone know if there is a drop in replacement for this engine

Massimo Rimoldi · « **Reply #1 on:** September 09, 2015, 01:30:45 AM »

Entire series STALKER (.61-.66-.76)

Regards, Massimo

Allan Perret · « **Reply #2 on:** September 13, 2015, 07:39:16 PM »

Quote from: Massimo Rimoldi on September 09, 2015, 01:30:45 AM

Entire series STALKER (.61-.66-.76)

Regards, Massimo

Not exactly. I recently aquired a DR60 and compared it to my Stalker 61.
The lateral spacing of mounting holes is slighty wider on the Stalker, about a 1.5mm.
Big Ron now has the DR60, going into his new UHP Impact ARC, which came predrilled for that engine and also support stub for rear of muffler.

Massimo Rimoldi · « **Reply #3 on:** September 14, 2015, 01:25:41 AM »

Quote from: Allan Perret on September 13, 2015, 07:39:16 PM

Not exactly. I recently aquired a DR60 and compared it to my Stalker 61.
The lateral spacing of mounting holes is slighty wider on the Stalker, about a 1.5mm.
Big Ron now has the DR60, going into his new UHP Impact ARC, which came predrilled for that engine and also support stub for rear of muffler.

It is true, in effect a small difference exists.
The problem can be solved ovalize slightly the holes.

Massimo.

Lauri Malila · « **Reply #4 on:** September 14, 2015, 09:54:35 AM »

Another drop-in replacement would be the Retro .76.
Just the needle valve position is a few mm differend. L

Allan Perret · « **Reply #5 on:** September 14, 2015, 10:55:33 AM »

Quote from: Lauri Malila on September 14, 2015, 09:54:35 AM

Another drop-in replacement would be the Retro .76.
Just the needle valve position is a few mm differend. L

Do you know the price on that one ? I think the DR60 will have plenty of muscle for BigRon's Impact, weight will be 62oz.

Massimo Rimoldi · « **Reply #6 on:** September 14, 2015, 11:00:53 AM »

Quote from: Lauri Malila on September 14, 2015, 09:54:35 AM

Another drop-in replacement would be the Retro .76.
Just the needle valve position is a few mm differend. L

Hello Lauri,
The problem in this case may be to find the engine.
I aspect a DR for about 2 years.

Massimo.

Lauri Malila · « **Reply #7 on:** September 14, 2015, 11:01:45 AM »

Extra power never hurts:)
It's been many years since I paid something for an engine, my guess is it was between 250 and 300€. But You'd better ask Directly from Yuriy.

Lauri Malila · « **Reply #8 on:** September 14, 2015, 11:07:04 AM »

Yes Massimo, I know. Sometimes it is better to buy the engine with a model

I don't fly with Retro much anymore but I must check if I have any still hidden in my workshop. I should at least have a few very good .60's.
L

big ron · « **Reply #9 on:** September 14, 2015, 01:11:26 PM »

Any info on running this engine would help also.

Lauri Malila · « **Reply #10 on:** September 14, 2015, 01:26:16 PM »

Do you mean DR .60 & .75?
I have written about the subject allready, please use the search first. L

Allan Perret · « **Reply #11 on:** September 14, 2015, 08:06:53 PM »

Big Ron needs set up info on the DR60LS in the 62oz Impact. Looking for fuel and prop recommendations, and tank size. He got the DR from me and I am coaching him.. I have a Stalker76 waiting in the wings if necessary.

Lauri Malila · « **Reply #12 on:** September 14, 2015, 11:05:02 PM »

If the engine is in stock condition, I mean original venturi and 0,6mm squish clearance, then it's best to use 80/20 fuel and original 13,4x5,9..6" prop from Yuriy. Start with full castor fuel and then compare with differend syhthetic oils - not all synthetics work well.
Usually about 5% of synthetic in the mix is enough to keep the engine clean. We use Motul Micro 2T oil, it works well.
Maybe you should ask Orestes about suitable fuels that are available in US..?
Fuel tank size is about 100..120ml. Fuel pick-up point (tank rear right corner) shoud be 5..10mm outside the center of venturi.
Best plug is the obsolete Russian KC-2, you can also try Enya #3.
Make sure there are no leaks in fuel- or exhaust system. I use red silicone putty to seal the needle valve/case connection but you must be carefull with that. Also, it's a good idea to replace the exhaust o-ring with a better Viton one.
The model sounds a little heavy, I hope the .60 has enough power.

L

Allan Perret · « **Reply #13 on:** September 15, 2015, 06:55:55 AM »

Quote from: Lauri Malila on September 14, 2015, 11:05:02 PM

If the engine is in stock condition, I mean original venturi and 0,6mm squish clearance, then it's best to use 80/20 fuel and original 13,4x5,9..6" prop from Yuriy. Start with full castor fuel and then compare with differend syhthetic oils - not all synthetics work well.
Usually about 5% of synthetic in the mix is enough to keep the engine clean. We use Motul Micro 2T oil, it works well.
Maybe you should ask Orestes about suitable fuels that are available in US..?
Fuel tank size is about 100..120ml. Fuel pick-up point (tank rear right corner) shoud be 5..10mm outside the center of venturi.
Best plug is the obsolete Russian KC-2, you can also try Enya #3.
Make sure there are no leaks in fuel- or exhaust system. I use red silicone putty to seal the needle valve/case connection but you must be carefull with that. Also, it's a good idea to replace the exhaust o-ring with a better Viton one.
The model sounds a little heavy, I hope the .60 has enough power

Yes motor is stock. Don't understand the full castor recommendation. What are the materials of piston and sleeve? Seems like the popular trend is to most if not all syn lube with modern metallurgy motors.. Just to comfirm on the 80/20 fuel, were talking FAI no nitro, right ?

Lauri Malila · « **Reply #14 on:** September 15, 2015, 07:51:55 AM »

Quote from: Allan Perret on September 15, 2015, 06:55:55 AM

Yes motor is stock. Don't understand the full castor recommendation. What are the materials of piston and sleeve? Seems like the popular trend is to most if not all syn lube with modern metallurgy motors.. Just to comfirm on the 80/20 fuel, were talking FAI no nitro, right ?

Yes, 80/20 is the "FAI fuel", 80% methanol and 20% good castor oil.
Retro has ABC construction, chromed brass sleeve with aluminium alloy piston. I measured 22..24% silicon content from one piston. I'd prefer slightly more.
The .60 runs best with full castor fuel. But then you must live with carbon buildup and other castor-related issues.
There are 2 reasons why it likes castor;
-castor oil tolerates higher compression and temperature before it starts burning. Many synthetics burn at lower temperature and can cause detonation.
-castor oil film tolerates higher surface pressure. You can easily hear it when priming a cold engine, with synthetic oil the engine squeaks more. Piston/cylinder fitting is quite tight in tdc. Tighter than the popular trend.
You can waste a lot of time with differend running issues if fuel is not good. It's better to learn first how the engine should run, with all-castor fuel and then compare other kind of fuels with that. Often people are stubborn and start messing with head shims and venturi, when the easiest solution would be to use correct fuel.
As I wrote earlier, we have good experience with Motul Micro 2T oil. I think it's a castor/synth blend allready, at least it behaves much like castor oil and keeps the engine more clean.
If your engine has never been run, I recommend at least removing the head and backplate and checking that thereare no foreign particles inside.
Which version do you have? The older with front lugs (remove them) or the new lighter with off-center cylinder?
L

Allan Perret · « **Reply #15 on:** September 15, 2015, 08:04:54 AM »

Quote from: Lauri Malila on September 15, 2015, 07:51:55 AM

Yes, 80/20 is the "FAI fuel", 80% methanol and 20% good castor oil.
Retro has ABC construction, chromed brass sleeve with aluminium alloy piston. I measured 22..24% silicon content from one piston. I'd prefer slightly more.
The .60 runs best with full castor fuel. But then you must live with carbon buildup and other castor-related issues.
There are 2 reasons why it likes castor;
-castor oil tolerates higher compression and temperature before it starts burning. Many synthetics burn at lower temperature and can cause detonation.
-castor oil film tolerates higher surface pressure. You can easily hear it when priming a cold engine, with synthetic oil the engine squeaks more. Piston/cylinder fitting is quite tight in tdc. Tighter than the popular trend.
You can waste a lot of time with differend running issues if fuel is not good. It's better to learn first how the engine should run, with all-castor fuel and then compare other kind of fuels with that. Often people are stubborn and start messing with head shims and venturi, when the easiest solution would be to use correct fuel.
As I wrote earlier, we have good experience with Motul Micro 2T oil. I think it's a castor/synth blend allready, at least it behaves much like castor oil and keeps the engine more clean.
If your engine has never been run, I recommend at least removing the head and backplate and checking that thereare no foreign particles inside.
Which version do you have? The older with front lugs (remove them) or the new lighter with off-center cylinder?

I bought the engine 2nd hand, advertised as new. Does not appear to have ever been mounted or run. It has the front lugs. Removal recommendation is just for weight ? Appreciate the help, good to know this info on an unfamiliar motor.

Lauri Malila · « **Reply #16 on:** September 15, 2015, 08:13:53 AM »

The front lugs are not necessary if you have good dural pads under the rear lugs. The shaft bearings are also a little happier when nothing is holding the front end.
Weight is not an issue, you can also just carve some clearance between the front lugs and engine bearers.

José Almeida · « **Reply #17 on:** September 15, 2015, 09:36:52 AM »

Hi Allan.

In the beginning when start with Retro Discovery engines, I had use FAI fuel with 20% Castor Oil. However, had problems with 2 engines, with lots of carbon on top piston and some clearances at rod holes.

I talk with Yuri and and show him the engines and advise me to use new fuel with different percentages and no normal castor oil
In this weekend, we are in competition in France and beg me the engines and replace all set of piston, liner, rod, etc. and give me fuel for entire competition.
The engines work so well without running-in. Great

Since that, my fuel always have 22% of oil ( 11% Castor Oil and 11% Synthetic) and no more problems with RD60 engines till today. Only when fly at Spain, I use 5% of Nitro and head shim, for oxygenate the fuel, because of altitude.
The real problem, is the castor oil. You find some kinds of theme but with different compositions.
Don't use industrial or medical castor oil. Have lot of sugar in his composition, especially medical! Burns a lot and create lots of carbon at combustion camera and in all exhaust system.

I use CASTROL M castor oil, from Castrol brand mix with other good synthetic oil, like Micro Motul 2T.
Normally use with better performance, the "Carbolin" like Yuri advise. After 100 flights, all combustion camera are completed clean and like a new

(*Castrol M is a specialist lubricant formulated from first pressings castor oil. As such it affords a high degree of purity and is free from contaminants.
*Castrol M is primarily recommended for use as a lubricant for model aircraft engines using methanol fuel).

About glow plugs and props, I agree with Lauri. The KC 2 Volts glow plug without bar and the Yuri wood prop 13,4 x 5,9. Usually picks at 1st ou 2nd.

Allan Perret · « **Reply #18 on:** September 15, 2015, 01:29:04 PM »

Quote from: Lauri Malila on September 14, 2015, 11:05:02 PM

Fuel tank size is about 100..120ml. Fuel pick-up point (tank rear right corner) shoud be 5..10mm outside the center of venturi.

How critical is this. I don't think that will be possible with the inverted motor mounting of the Impact. It will be more like 25mm.

Lauri Malila · « **Reply #19 on:** September 15, 2015, 01:58:54 PM »

Quote from: Allan Perret on September 15, 2015, 01:29:04 PM

How critical is this. I don't think that will be possible with the inverted motor mounting of the Impact. It will be more like 25mm.

Yes Allan, I thought about is right after writing..
That's one good reason to mount the engine horizontally..
I know that the first generation of Yuriys and Andreys models had it cylinder down so there must be a way to make it work properly. At least the fuel tank is so small that you can make it slightly taller and narrower and mount it near the left side of fuselage.
When tank is too much "out", the needle setting before take-off has zo be slightly richer so it leans to good setting once in flying speed. My main worry would be richening in overhead maneuvres.
One more thing, as you have the muffler right under fuel tank, you better insulate the tank well against heat. Otherwise the engine will get richer towards end of flight as the fuel warms up. You can compensate it slightly by tilting the fuel tank pick-up corner more out than front-right corner but not very much. I cover my tanks with soft 3/32..1/8" balsa and aluminized Mylar, it helps a lot.
But I will see the Yatsenko Bros. in a couple of weeks time, I'll ask for Yura's recommendation regarding the fuel tank.

From Moscow,

Лаури

Chris Wilson · « **Reply #20 on:** September 15, 2015, 03:22:04 PM »

Quote from: Lauri Malila on September 15, 2015, 08:13:53 AM

The front lugs are not necessary if you have good dural pads under the rear lugs. The shaft bearings are also a little happier when nothing is holding the front end.
Weight is not an issue, you can also just carve some clearance between the front lugs and engine bearers.

As an aside, the R&B Metamorphs have the same 6 bolt/ front lug pattern and I was wondering about the validity of the front mounts also.

Thanks.

David Zwolak · « **Reply #21 on:** September 15, 2015, 03:34:05 PM »

Has anyone been able to get a DR from Yuri within the past year or so? He lists on E-bay. But queries go unanswered. Is he still supplying DR engines?

Lauri Malila · « **Reply #22 on:** September 15, 2015, 04:00:06 PM »

Yuriy makes the DR engines but he also makes everything else he sells and at the same time tries to catch up with new technology. In that light it is quite understandable that it's often easier to get an engine so that it's bolted into a model. He is more interested in perfecting his stuff than making it a good business.
But now he seems to be working on a new 11cc engine.
About the front lugs, ideally the front mounting point should be somewhere between front and rear bearing, and the rear mounting holes somewhere near the rear of carter. You can see that kind of mounting in many racing engines, many of those guys are a lot smarter than us.
The standard bolt pattern is just easier for model builder.
I tried the 6-bolt mounting with the first versions of our .77 engine but soon found out that it's better to let the front end live its own life during maneuvres. But our carter is much lighter, I don't think it makes a big difference with Retro. L

Daniel_Munro · « **Reply #23 on:** September 17, 2015, 12:10:53 AM »

Quote from: David Zwolak on September 15, 2015, 03:34:05 PM

Has anyone been able to get a DR from Yuri within the past year or so? He lists on E-bay. But queries go unanswered. Is he still supplying DR engines?

I was in touch with Yuriy a couple of months ago about buying a Retro Discovery 76. He recommended I buy his new Retro Discovery .69 instead. I am yet to purchase but his email address can be got from the following website..... http://discovery-aeromodels.com

As for oil in these Ukrainian engines I can speak for using full synthetic in my Stalker .51re. I was using Klotz 80/20 synthetic/castor blend. I recently moved to Klotz full synthetic and have noticed an increase in power as well as a very consistent run. I've not needed to touch the needle since.

I don't know how Stalker engines compare to Retro Discovery, but they seem similar.

Chris Wilson · « **Reply #24 on:** September 17, 2015, 09:00:07 PM »

Quote from: Lauri Malila on September 15, 2015, 07:51:55 AM

There are 2 reasons why it likes castor;
-castor oil tolerates higher compression and temperature before it starts burning. Many synthetics burn at lower temperature and can cause detonation.
-castor oil film tolerates higher surface pressure. You can easily hear it when priming a cold engine, with synthetic oil the engine squeaks more. Piston/cylinder fitting is quite tight in tdc. Tighter than the popular trend.

The higher compression and temperature mention makes perfect sense and I remember pondering about high compression MVVS engines years ago that stated that they were designed for castor oil, as in how does one 'design' an engine for a certain oil?

Thanks Laurie.

Steve Helmick · « **Reply #25 on:** September 20, 2015, 09:54:32 PM »

My friend in Sydney, Dave Simons, has/had an early Yatsenko plane & DR.60. He had problems with a "Fox Burp" situation with the engine inverted as it came, and contacted the DR factory about it, eventually shipping it back to Ukraine, suggesting they mount the engine sideways. When it came back, it was not sideways, but canted about 45 degrees down & to the outside. Dave said it worked perfectly that way. Say "G'day" for me!

My buddy in AZ, Gary Gingerich, sometimes flies up for a NW Regionals or Prairie Fire contest in Edmonton with his Yak 54 (?) with the DR .76, and I make him a gallon of fuel. IIRC, he specifies 5% nitro, 5% castor, 15% Ucon and 75% methanol. He said it worked great. Since Gary isn't online, I got him a couple of "Rainbow" 14 x 6.5's from Kaz. Real expensive, at about $75 for two! I'd have to make props myself from a Zinger kit. Good advise can be gotten from Kaz, of course.

Steve