OS61 - Hanno Special?

[Ian Whittaker]

Hi, 

I’ve just picked up a second hand model with a OS61 upfront. It’s marked as OS Max 61 RF on the crankcase. It’s fitted with a pump and also a exhaust header to a tuned pipe. There’s stickers on the fuselage and wings proclaiming it to be a ‘Hanno Special’. Do this sound reasonable? What is a Hanno Special? I’ve been searching the internet and apparently Hanno Specials are a bit of a limited edition? Can anybody pour any light on this please? 
thanks!

Ian 

[Gary Manuel]

Here's some bumph in case you haven't seen it Ian.

http://sceptreflight.com/Model Engine Tests/Hanno Special ABC.html

 

[Denis Watkins]

41 minutes ago, Ian Whittaker said:

Hi, 

I’ve just picked up a second hand model with a OS61 upfront. It’s marked as OS Max 61 RF on the crankcase. It’s fitted with a pump and also a exhaust header to a tuned pipe. There’s stickers on the fuselage and wings proclaiming it to be a ‘Hanno Special’. Do this sound reasonable? What is a Hanno Special? I’ve been searching the internet and apparently Hanno Specials are a bit of a limited edition? Can anybody pour any light on this please? 
thanks!

Ian 

 

I don't know how many were made Ian

It was Limited

1989 OS MAX-61 RF 

Is ABC so tight at the top when cold

Hanno Special 9.97cc 

 

Oh Gary sorted it, while I was typing

 

Edited April 27, 2021 by Denis Watkins

[Ian Whittaker]

Thank you, I’m a little wiser! 

[Ian Whittaker]

I need to whip it back out to see if there a serial number on the LH mount I think! 

[Alan Hilton]

The Hano special had a red anodised head and the pump had one inlet and one output .The earlier RF pumper had a silver head and four inlets and outputs on the pump . The very early RF pumper had a small rear bearing which lasted no time .The later RF and the Hano had a larger rear bearing which also lasted badly .Mainly I believe due crank case flexing .They both need at least 10% nitro to run properly Best prop on the Hano I found was a 12.5x11 ,on the RF a 12x10 

Alan

[Don Fry]

If you start the beast, you will realize what special is. From memory, the pipe is a bit short. So, if you start a climb, ie a loop, as the load comes on, revs drop, the pipe comes on tune, and it will grunt harder to haul the airframe up, reducing pilot workload, ditto, second half of loop. Never owned one, but used to watch practitioners exercising them. 
They drink fuel. Shove in an acrobatic machine and they are great, but not quiet. They did not run for huge hours between knowledgeable people rebuilding them.

Alan is about right I think, bearings were on the limit. But, in their day, out performed a F1 engine, KW per Kg.

In 2021, the bearings might last better. We have better oils today. In their day, I bet, the very best machinists made the components.

Edited April 27, 2021 by Don Fry
Adding last paragraph.

[Andy Stephenson]

There's a thread on RC Groups where you can put you're name down for a replacement piston and liner set for the Hanno/RF as many of them had problems with the original liners stripping their plating. The guy who makes these operates from Australia and he makes a superb job of them, I had a set he made in the first run. Ian, it's best to take the head off and inspect the liner before you use it. See this thread...

https://www.rcgroups.com/forums/showthread.php?3380853-Making-ABC-piston-liner-rod-pin-sets-for-O-S-61SF-RF-engines-(tally-in-OP). Brian is taking names for a second run so if you need to recondition your engine now is the time to get on the list.

[Ian Whittaker]

It certainly has a red head and also the pump has two connections. I have actually run it up, it seems to go well enough but I haven’t got a tachometer round it. 

[FlyinBrian]

You lucky B - ah devil!

[Nigel R]

That was a lucky buy. 

Could certainly fund a few other toys if you decide to auction it off.

 

I would second what Andy says. I have had terrible luck with the lines in second hand os motors of that age and size. 

[Andy Stephenson]

On 27/04/2021 at 19:33, Don Fry said:

If you start the beast, you will realize what special is. From memory, the pipe is a bit short. So, if you start a climb, ie a loop, as the load comes on, revs drop, the pipe comes on tune, and it will grunt harder to haul the airframe up, reducing pilot workload, ditto, second half of loop. Never owned one, but used to watch practitioners exercising them. 
They drink fuel. Shove in an acrobatic machine and they are great, but not quiet. They did not run for huge hours between knowledgeable people rebuilding them.

Alan is about right I think, bearings were on the limit. But, in their day, out performed a F1 engine, KW per Kg.

In 2021, the bearings might last better. We have better oils today. In their day, I bet, the very best machinists made the components.

Don,

I've been rereading your post and it seems to me that if the pipe comes on tune when revs drop wouldn't it have been too long at higher revs and not too short. Shorter pipe for higher revs,  longer pipe for lower revs.

[Nigel R]

Concur.

 

Andy, have you run your Gardner liner yet?

 

 

[Don Fry]

You might well be right Andy, long time ago, never my thing. Your explanation makes sense.

[Andy Stephenson]

Nigel,

I have had it fitted for a while but I haven't run it yet. I will have to take it up to the flying field as running it at home may be one run too many for the neighbours. 6 x 1 minute runs at full throttle with absolutely no tick-over, this is what Brian has prescribed for running-in.

I'm not sure what prop to use but probably a fairly light load like a 12 x 8.

These liners are made to the Hanno spec rather than the original RF spec which means the exhaust timing is slightly different. I understand that this will mean more torque at a lower RPM on my RF.

[Nigel R]

Yes, that's a fair amount of time if you count the cool down periods. It is made slightly easier on the SF by virtue of standard silencer being usable. But like you, it will be a field trip for the initial handful of runs. In between the SF runs I also have a ringed SF to run in ?

 

Next on my build list is a Calypso or Rocket. Plan is to run the SF with a standard silencer and 12x6 for a couple of sessions before moving to the full pipe install.

 

Edited April 29, 2021 by Nigel R

[Bruce Collinson]

My Rocket has been waiting for spray for so long, it transpires that the Oracolour hardener is out of date.   All ours (4 or 5, Terry Anderson is a clubmate) run on Saito 100s as we don’t fly 2 strokes for noise reasons.   Lovely plane.   I think Terry has tweaked it a little latterly.

BTC

[Nigel R]

Any idea what the tweaks are?

 

[Bruce Collinson]

I will ask him but I suspect he tweaks a bit with every successive version.   Might be able to get a current plan if it helps.

B

[Nigel R]

I'd happily settle for just knowing (roughly) what the tweaks are! ?

 

[Bruce Collinson]

As a technophobe, if you email me I will forward to Terry.

 

BTC

[Ian Whittaker]

On 27/04/2021 at 20:36, Nigel R said:

That was a lucky buy.

Could certainly fund a few other toys if you decide to auction it off.

 

How much roughly are these engines worth now please? I can’t see me using it in a competitive manner so could swap it for something different if the Hanno would help someone else. I could easily find another engine to haul my airframe around the sky...

[Robin Colbourne]

There's one on Ebay at the moment, allegedly a Hanno Special:  Hanno Special? on Ebay

[Nigel R]

It's serial numbered, probably legit. Wait and see what that one goes for.

 

Clean, working order? At least a couple of hundred I would guess, maybe more. Shoot a video of it running. Even the standard used SF/RF can fetching up to near a hundred, if clean. If you have the matching red OS pipe then you found a small gold mine.

 

Seem to remember a new in box example was listed (and sold apparently) at the thick end of £1k not long back, just the motor.

[Ian Whittaker]