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Old Apr 13, 2014, 07:56 AM
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Graupner/Heim Mini StarRanger

Did anybody ever build and fly these in the long gone past?

I picked one up, in virgin condition, and I am trying to build a Raptor 30 into it.

Was wondering how they flew and worked in the old days (mine has production date June '91 printed on it....) with the old Heim mechanics they were designed for....

Brgds, Bert
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Old Apr 13, 2014, 07:38 PM
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Bert
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Old Apr 15, 2014, 11:21 AM
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Slowly gettin'there....

The engine had its first start with electronic ignition...

VVery first start of my OS .37 SZ with electronic ignition (0 min 37 sec)


Brgds, Bert
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Old Apr 21, 2014, 12:07 AM
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what engine did you install there ?
is it running on gas or glow without nitro ?
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Old Apr 21, 2014, 03:03 AM
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what engine did you install there ?
is it running on gas or glow without nitro ?
Engine is an OS .37 SZ-Hring, and it is running on 2% Nitromethane, 15% full synthetic oil (Carbulin) and balance Methanol (83%)

The 2% Nitro are there because we also sell home-blended fuel and don't want to have to keep too many different fuelblends in stock.

With CDI, just a mere 2% Nitro make a huge difference in ease of carburettor adjustment.

We are NOT running gas, because the cooling of glow engines seems just not designed for it.

On a side note: we have discovered a peculiar side-effect of CDI. Due to the oil separating from the fuel in a different way, helicopters with the crankshaft pointing upwards have a very strong tendency towards hydrolock when starting. This can be prevented by either storing the helicopter with the exhaust port pointing down (laying the heli flat on its side usually) or storing it with the cylinder head pointing upwards.

This to prevent the combustion chamber from flooding with oil at standstill....

Brgds, Bert
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Old Apr 22, 2014, 01:35 AM
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Yesterday it got its maiden hoover.

Since it is basically a high powered Raptor 30, now it is a medium powered fueselage-heli. Feels like a heavy raptor, not much more to say about that.

Since I have been virtually exclusively flying tuned piped for the last 2 decades, the standard muffler makes for slightly more difficult to set throttle curves.
The standard muffler is also pretty noisy, but unfortunately the Zimmermann muffler that the donor heli came with, did not fit inside the body...

The engine has been operated on a fuel containing (a little bit) Castor Oil by its previous owner, and that means that I have to carefully flush out the Castor resin "coating", and resume the breaking in that has been effectively halted by this resin coating, before I can lean it out to max and get the optimum fuel consumption that I am looking for with this machine.

This is how it looks now. Once I have established the reliability a further paint job will be done.

Brgds, Bert
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Old Apr 27, 2014, 10:00 AM
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Just a short impression....

Short because it was raining at the time, and also because Raptors do not have the most optimal cooling system, and I still have to make some improvements on that....

I am not piloting on this video....

Mini StarRanger CDI (0 min 47 sec)


Brgds, Bert
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Old May 03, 2014, 03:22 PM
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It flies great:
Gewoon een vluchtje met de Mini Star ranger... (1 min 38 sec)


but unfortunately, something went wrong with the engine (unintended stop at the end of this vid), but I managed to get her down in one piece....
En toen ging er iets mis.... (1 min 19 sec)


I did not yet find time to dismantle the engine, but I could establish the conrod etc are OK but compression has gone, and the piston (as far as I could see) shows a scratch in the line of the wristpin, so maybe one of the G-clips has failed....

Would be a shame....

Brgds, Bert
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Old May 15, 2014, 11:55 AM
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When dismantling the engine, I found the gudgeon pin more or les stick in the small end bearing (not seized, but not moving free, most likely due castor oil residue) and this might have lead to the teflon pad separating the gudgeon pin from the liner, to be force pressed to the liner, effectively wiping away the oil film for the piston ring, like a window wiper....

This made the ring score the liner, and in turn the liner score the piston.
Because apart from this, ALL other moving parts, including the remaining circumference of the piston, ring and liner, showed excellent lubrication and running behaviour.

In the meantime replaced the engine for an ASP, to which the ignition sensor fitted without ANY modifications to the engine.

Still in the breaking in process, but very, VERY promising, since the thermal design of the ASP seems to be a LOT betterthan that of the OS....

Brgds, Bert
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Old May 16, 2014, 01:19 PM
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Bert man!! Just stick a big a$$ brushless in there man;

What you're describing sounds like the kind of nightmares I had to deal with RC nitro cars back in the day... carb needs tuning... sleeve is almost done... doesn't start... needs better cooling... won't start... (piston on cars always sits straight up so no issues with flooding, except when carb wasn't tuned right)

G.
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Old May 17, 2014, 01:42 AM
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Hahaha.... you don't get it, do you?

I LIKE this tinkering, and "figuring out how".

Like I said in the other thread, I am not in it only for the flying... if I didn't build it myself, I don't really like flying it.
I prefer a problematic design I did myself, over a perfect "off the shelf" machine.

I am not the kind of guy that does not care what makes the rotor spin, rather I am the kind of guy that takes interest in the power generation....

Brushless=boring....

Brgds, Bert
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Old May 18, 2014, 12:34 PM
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Originally Posted by Brutus1967 View Post
Hahaha.... you don't get it, do you?

I LIKE this tinkering, and "figuring out how".

Like I said in the other thread, I am not in it only for the flying... if I didn't build it myself, I don't really like flying it.
I prefer a problematic design I did myself, over a perfect "off the shelf" machine.

I am not the kind of guy that does not care what makes the rotor spin, rather I am the kind of guy that takes interest in the power generation....

Brushless=boring....

Brgds, Bert
I agree with you, looks like we just like different power sources. Do you have a video of your redbull Vario?

G.
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Old May 18, 2014, 01:18 PM
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I agree with you, looks like we just like different power sources. Do you have a video of your redbull Vario?

G.
Nice weather:

Vario Bo-105 Bert.wmv (2 min 54 sec)


and at 4~5 Bft:

Vliegen bij Helischool Oldeberkoop | Bert de piloot (3 min 16 sec)


And a 450 size BO 105 at the same windy day as the previous clip:

450 size BO-105 (high wind no estab) (3 min 4 sec)


All non-E-stab multiblade: I like to do the flying myself too

This is my Bell 47G II: fourstroke, CDI, two bladed but flybarless, non-E-stab as well

Vario Bell 47G Bert.wmv (4 min 31 sec)


And like I said, I like to tinker, this is my flight school helicopter with 2-stroke and CDI, runs smoother than an electric motor:

Vario Skyfox with sparkplug ignition (4 min 44 sec)


Some more tinkering, still glowplug but converted to liquid cooling....

Vario Xtreme liquid cooled engine.wmv (7 min 19 sec)
(and of course non-E-stab)


You can find my other modelling stuff under "rigididiot" on youtube...

Brgds, Bert
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Old May 19, 2014, 01:01 AM
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sweete mother!! wow! That is some impressive stuff... I like your BO-105! I've seen the videos of the redbull one doing some crazy stunts (for a full size that is)

So, what did you do to convert to liquid cooling? Did you used some of the water jacket for boat engines?

BTW, I am all GPS-stabi now; bare flybarless e-stabi is so last decade... "all show and very little go these days"

My channel in youtube is MiniBichus (there are two, both are mine)

G.
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Old May 19, 2014, 01:18 AM
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sweete mother!! wow! That is some impressive stuff... I like your BO-105! I've seen the videos of the redbull one doing some crazy stunts (for a full size that is)
That is my biggest problem: my flying style does not match the colour scheme....

Quote:
Originally Posted by Minibichus View Post
So, what did you do to convert to liquid cooling? Did you used some of the water jacket for boat engines?
I made a jacket with real big inlet and outlet, and a (relatively) large water content, on the lathe, built a radiator out of some aluminium and brass tubing and thin Alu sheet metal (got a little help there from a friend with a milling machine, fabricating the fin-package). The tubing is just Tygon.

That is basically it: filled it with demi-water and coolant Antifreeze (25%) and the circulation is natural (thermal).

In a continuous hoover, the radiator does not get enough air flow, but it holds out for roughly 3 minutes before it boils out, and that is plenty of time for any landing or take off manouvre.
In flight, the cooling increases so much that I had to use baffles to prevent overcooling it....
I still have to modify to a better location, picking up more rotorwash and less flight-induced flow...

Quote:
Originally Posted by Minibichus View Post
BTW, I am all GPS-stabi now; bare flybarless e-stabi is so last decade... "all show and very little go these days"
That, my friend, for me is literally a nightmare.... I could live with receivers that have that option built in but you can switch it off.... but I fear, in 10 years it will be included and NOT selectable.... Oh, horror.... Oh dread....

It would, no joke, mean the end of a beautiful hobby for me.... there is no pride in being able to fly a helicopter, if for everybody else that is just a matter of programming your GPS and pushing a button....

Quote:
Originally Posted by Minibichus View Post
My channel in youtube is MiniBichus (there are two, both are mine)

G.
I'll have a look....

Brgds, Bert
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