Gentlemen, has anyone out there had experience with the HB 61 engine, in control line configuration? I believe it's a German engine. If so, I would appreciate any input regarding general performance, type of fuel used, propeller and planed it was in. Would it perform well in a Brodak T-Rex (ARF)?
Thanks for your comments
Ferenc

Seems theres more than a few " H B 61 " engines .

Like this , & schneurle .



One never knows , Some of the Webra 60s look like they may be promising , if you like the weight ( short nose ) .
The timing on those vary significantly according to type .H B presumeably so too .

A protractor / timing disc - a pointer under the lug . find T D C & B D C , use a lamp or flashlight .
Intake out ( and head off on a balled piston ) & its easy to figure the openings & closings .

About all thatll trip you up is excessive ' blow down ' maybe. And a exhaust up past 75/150 degrees it gunna wanna rev like snot .



Francis Beart or someone had a three foot diameter one that went down to 1/10 th degrees , or suchlike . For accuaracy .
Your looking for the opening and closing points , swing back & forward past them a few times to get in on them exact .

BETTER to just fire it up , richen to four stroke , then pinch the fuel tube on & off for a while for varying times and degrees .

It should drop straight back into a four stroke . of have a rev range where it backs off straigthaway the tubes released .

If it dithers and prevaricates its likely notta lotta use . Cept maybe one speed fine pitch two stroke run in a big mutha.

Mostly 20 % oils about right , for a ringed ball race engine .

RUNNING IN , 30 % for the first pint , 25 for the second .
 And a Half Litre of Beer IS NOT A PINT . Bimbos ! its short changeing 20 % .
unless its a American Pint . But American percentages Still Match ! 

Where were we .  Useually I run 23 % , useing 3 % Synthetic .  HOWEVER Tom Lay ( T & L Engines )
Recomended ALL CASTOR sateing Ring Life Doubled .

As Ive been getting grief with runs lately , I think the Full Castor is the way .
 If the oils poor or carbony , the 3 % Syn should keep it ' washed ' in use .

ABCs are a differant story . A run on 9/9/15 N on the ST 46 cleaned it out nicely , ran well . Lowered Comp . ' braced ' the ring nice & shiney
Lucky the Comp. came back up on the next run on all castor . 

If its summer , No Nitros probably tolerable . regards needle settings . If it steady & sets easilly , no worries.

Most run 10 % , and get a broad easy neddle to set . Saves a lot of wasted flights .

Sometimes No Nitro you prime with Nitro fuel - or lighter fluid , to get the engine to light up .
Can be dead as a doornail with a chill in the air .

Many experts advise MORE NITRO will mean it will run COOLER . Certainly It broadens the setting . But you must run RICH .
Then itll provide a ton of tourque and swing plenty of lumber ( prop ).                                                        ====

High Summer you may want to run 25 % - 27 % oil , to cool & lube , if no nitro .

THERES SOME VERY GOOD  posts fixed at the TOP OF THE PAGE , General Info . Mr Smith / Aero Products . For a general read .

Anything that wont swing a 12 x 6 at 10.000 is a whimp . A Veco 45 would.unmuffled . Any 60 should . muffled . as a test .
.60 baffle intakes generally 0.285 inch to 0.320 inch . .312 / 315was the ' Big Jim ' size . were told . So a reasonable start
if your playing big .
A weeny little 46 ship .285 / .290 is likely plenty .

You likely want to try two or three differant design mufflers , as they can make or break your day , as regards run characteristics . 

HB61 would not be my engine choice for a big heavy T rex arf. Just not enough power.

Really??  Jus' curious … what would you suspect the RTF weight of a T-Rex to be … without engine?  3 maybe 4 pounds??  Yet the same engine but r/c, can haul an 8-9 pound r/c plane around at about 60 to 70+ mph! (I'm speaking from experience  )

Probably all the drag from the lines is one of the causes of reduced performance.
Helmut Bernheart? imported Veco engines before he launched his lineup. I used HB not to be confused with HP engines and always found them to be good solid reliable engines. I was flying RC after 72 so Most of the engines that I used were really up to the tasks required from them. The tragedy was that the Veco and probably the HB were about an ounce heavier than the ST 60 so no matter how good it was I'm sure it was moved to the workshop drawer never to prove how good they really were.

Understood and acknowledged!  However, it would be interesting to get some idea as to the amount of drag that would be induced from a set of .018 x 60 - 65' lines holding a 5lb somewhat clean airship with such an engine running near its performance/ power curve?    I'm thinking it would be far from underpowered.