I'm looking for anyone with experience running either the Discovery Retro 61 or the Double Star 60 to comment on the engines performance. What size model are you using, lap times, props, fuel, plugs etc. I'm looking for a replacement for my old ST60's that really had some grunt. I need lots of low RPM power and torque.
Engine Information
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I have a copy of a Tom Dixon review of the older K&B 61, not the twist head, in which he comes to the conclusion it is a one ounce heavier ST 60. From reviews I have read, it doesn't sound like either engine you mention is a new model ST 60.
Jim
This is what worked for me using the Double Star Lite 60 SE
Model - Modified Magnum
AUW - 63oz
Lines - 66ft E.T.E / (0.15 UK)
Fuel
12.5% Castor
12.5% klotz
10% Nitro
Plug - OS FS / OS No8
Tank - Uni flow
Prop - 13x4 APC
Take off RPM - 9200
Lap - 5.2
Tried 12x5/6 at lower RPM, but did not seem right, loaded up too much.
Good flying
Tony
Al, I did a review of the 2Star .60bb in the products report forum, tho it may have disappeared during one of several SSW server crashes. I bought it 3rd hand, bench run but unflown, and like it a lot. Plan is to put it into a Brodak Legacy or UHP Impact. I ran it in a 4th hand model that somwhat resembled an SV-11. I never could get any information on what it was, but it wasn't light. I liked it with an APC 12.5 x 6, T-bolt 4 stroke plug and 10 x 22 Powermaster. Otherwise, ran it just the way it came from the styrofoam box, except for installing socket head screws in place of the crumby factory screws, and a Randy Aero NVA. If you'd like to test fly it, that could be arranged. Steve
PS: My Ozzie buddy Dave Simons has a Retro Discovery .60, and had to change to side mount to make it run consistent speed inside/outside. I'll poke him with a stick, and get him to check this thread.
Hi Alan,
I remember that Tom Dixon was looking for a direct clone of the ST 60 Big Jim engines when he started work on the DS 60BB. The later *lite* was for reduced weight, and not sure what timing, etc., was used.
I remember that Tom Dixon was looking for a direct clone of the ST 60 Big Jim engines when he started work on the DS 60BB. The later *lite* was for reduced weight, and not sure what timing, etc., was used.
As to whether or not the BJ clone was achieved, someone with experience using them can tell you, not me. I have run the ST 60, but not the DS. 
A lot of fliers around here (SE) use DS in all sizes, but I have not seen many of the 60BB lately. Most are using the *lite* or RE, AFAIK.
Mr. Dixon also told me that the engines from the factory are set up for low/no nitro. They are easily overcompressed if you do not add shims when using nitro.
Most of the time the venturies/restrictors can be opened up a tad to increase power, on all sizes.
The hot fliers' set ups around here seem to only use nitro and head shims for varying conditions.
Bill <><
When the character of a man is not clear to you, look at his friends.
Japanese Proverb
Alan,
Been using the Retro for a couple of years, as well as a ST 60 & prefer the latest Retro.
Been using the Retro for a couple of years, as well as a ST 60 & prefer the latest Retro.
If you can see some video of the Yatsenko's flying at the w/champs & Nats, it will give you a good idea of how they run. The model that Yuri was flying is my current model, loaned to him for the w/champs & nats.
Model: yatsenko take apart - 58oz, about 680 sq.
Prop: 13.4 X 5.9 Yatsenko, wide blade.
Fuel: 4:1 (FAI) or 10castor, 10Klotz, 2 nitro, rest methanol
Plug: original Russian K2, but OS F or Enya #3 is OK.
Radius: 20.2m
lap time: 5.5-5.7, fast 4 stroke, constant speed.
In my experience, they work best side (or nearly) mounted, but some have got them to work fine inverted. I've had best results side mount.
Some observations - side mount anyway, they seem to resist wind-up in wind quite well and have a lovely linear needle response.
They also vibrate a bit when 4 sroking, but it's never caused a problem to me.
The very quiet exhaust has a distinctive note, judges like it.Engine/muffler is very light, I'll try to find the weight for you.
Comparison to the ST?. My ST has been tweaked by Brian Eather, runs great & seems to have a lot of grunt, on lots of nitro. I'd rate the Retro as not quite as powerful on straight fuel, & have never tried more than 5% nitro (which made no difference)- they are set up for no nitro fuel with lots of compression.
To be honest, I dont think the ST and Retro are comparable - the Retro is a clean sheet of paper design, meant to go with the rest of the "system" - which as a package works very well.
The problem I had with the original setup was that, despite being able to tune it for perfect inside/outside, it would break at the transition from inside/outside, H8's ferinstance. I couldn't cope with it, but some liked it that way, I have to admit it did killer V8's.
The latest engines have been changed & have a new crankcase casting with, I think, a smaller transfer passage. It runs at impressively constant speed. Tached on the same prop, and in the air (audio tach), the later engines seem a little stronger.
One notable feature is the beautiful piston/cylinder fit, made by the guys who do the Profi speed & TR engines, I believe. I think they will be a very long life engine.
Hope this helps,
Cheers, Dave
Steve, I'll consider myself prodded!