Vintage Glow Ducted Fan forum
 

Dear all,
Can you please let me know if there is a forum for old vintage glow ducted fan stuff? I'm working on some historical projects and need some info from those whom may have participated in this era.
Kind regards,
Rick

Many of us who fly turbines started out flying ducted fan and still love the nostalgia of them. This forum right here is likely where you'll find the answers you need. I'm not aware of a icdf jet forum specifically.

Okay,
Great! Well here it goes!
I recently completed an old school Kress / Scaropolous (SP?) Mini F-16. Half of the fun was the research, for that project - I was a young lad when it was the cutting edge and seemed so unobtainable to me. So that was great fun to go through. See attached eye candy photo.
This new project is from a bit later.
Byron Originals seemed to have brand labeled Rossi 90's, I guess they were a distributor for those glow motors? I see in some documentation around 1992 there were two engines. A "R 90-48" prior to July 1992 and a "R 90-58" which came later. Now I was chatting with someone they told me there is a "98" version of this motor?
Does anyone have any insight they are willing to share? I'd love to understand the differences and perhaps which motor was top of the heap at this time.

Much Thanks in advance and hope you enjoy the photo of my Mini-F16. I powered it with a .090 fan I build myself as well as with the RK-049 it was supposed to have.

Kind regards,
Rick

For a Byro-fan the best (and most reliable) engine there was is the OS .91 VRDF large head. If I recall correctly the Rossi could spin faster, but you had to do several mods to get them to run reliably.

OS .91 man!

If anyone needs a BVM on Board Mixture Control.....I have one for sale.

BVM DF ON-BOARD MIXTURE CONTROL (ID: 1116374)

Well, That's usually the case.

I like to use DA engines in my aerobatic airplanes not for power, they are not the most powerful, but the reliability and mid range response cannot be matched.

I am interested in the preferred power at the time and I have always been a fan of the OS. You have a great point there. I noticed several versions of those motors as well. A large as well as a small head. What's the difference and what to look out for with the OS engines?

Kind regards,
Rick

Here,
I'll continue some Eye candy for following along on my post. Here is what I call my own RPK-709 fan...
RP

Only difference between the large head and small head OS .91 VRDF was the cylinder head. Small head for Dynamax , Ramtec or similar tractor fan. Large head for Byron, Cobra or similar pusher fan.

Ok,
So the larger cylinder head versions are the pusher style fans. Got it! Thank you!

What are the tweaks required for the Rossi? Are they difficult to apply, or is it mostly trial and error?
Rick

The other issue with the Rossi is it was heavy by comparison. The OS is still relatively easy to find parts for and many new in box engines can be found via eBay and sites like this one. I never ran a Rossi but I do remember guys who did and they seemed to need to fiddle with them more than the OS or KBV/BVM engines.

Incidentally, the large head on the OS was to aid in cooling. The pusher fans did not direct airflow over the engine so they needed the heat sink head just like in a helicopter.

OS all the way, best reliability.
did some experimenting with the last Rossi ducted fan engine, it was the follow up for the 90, I think this was the 102.
it would not idle without a glow assistance , but if just left on full power it was really strong, very unreliable though, and it used conical glow plugs for whatever reason, Real Italian breed for sure. Oh, and NOISY !
even the Rossi 90 was pretty finicky, but decent if you got used to it.

I had one of the old Rossi .82's, ran ok but nowhere near as powerful as the OS .91.

I have a new in the box OS .91 small head if anyone is interested. :)

Way Back When, I started out in this hobby with a of Rossi 0.81 motor and Dynamax tractor fan, Installed in a Yellow A/C F-16C..
I could never get the Rossi reliable enough to actually fly, and eventually replaced it with an O.S. 91, and never looked back.

A friend of mine owned a Rossi 105 DF which was also very unreliable. He however, is a very talented mechanic, and persisted with it, although with a lot of modifications. Eventually it was a very powerful motor, driving the Ramtech fan unit although it was never as easy to operate as an O.S.

One of the many modifications required was to fit an OS carburettor, which was very expensive to purchase as a spare part.

byron version rossi and byron version os differed from the regular stock in the same way. byron versions had the big heat sink heads. do not know that they could be called "branded" though.

OS ,91 best all the way !! The K&B,82 was ok had midrange issues but better than the rossi's

Wow,
It seems like the results are in. I'd really need something with a solid idle and smooth transition. Even if it meant sacrificing a little power on the top end. I have found both motors NIB. Rossi 90-48, OS 91 small and large head. The last thing I really feel like doing is fooling with carburetors and such. I'm a fuel it up and fly type of guy. I don't want to be tinkering around under the hood at the field.

I've had great luck with OS in my pattern planes. Break them in really well, start right up and fly a full tank. In fact my last King Kobra I flew for two years I didn't ever have a single dead stick. Too bad I dumb thumbed it in. RIP.

I'll mull it over for another week before I make my choice. But I'm leaning heavy towards the OS now. Thanks guys.

RickP

Well - it is before my time really, but you could buy motors directly from Byron Originals and when you did the engine bosses were stamped with a "BO"

If you don't like tinkering with your airplane at the field, then run as fast as you can away from nitro ducted fan!! We used to spend all day sometimes just to get one successful run! And, without an in-flight mixture control you would get lean halfway through your flight amd dead stick. Make sure you have lots and lots of glow plugs because those motors are notorious for burning them up. And we haven't even begun to discuss the proper ammount of nitro and oil in your fuel yet, that can be a thread all on it's own.

If you want fuel and fly ease, buy a turbine or electric ducted fan.

Not trying to discourage you, just want you to be able to make an educated decision.

Good luck!

That's why he will benefit from those who spent a lot of time in the 80's-90's tinkering with fan/pipe/engine combinations. Lot's of combined knowledge out there.

I flew DFs from 2004-2006 and never had a dead stick. Stuck to very well know equipment combinations, and did blew up a couple of old fans in the ground, but for me it was worth it. Plus the cost of equipment is so dirt cheap nowadays ( Viofans with BVM 91's @ $250 average).

Rick will end up flying turbines.....he just doesn't know it yet. :-)

LOL,
Thanks guys. I didn't mean that I won't tinker, I just don't prefer it. I'd rather fool around on the bench and prepare as much as possible first so I minimize efforts at the field.

For me this is also a trip down memory lane and a nice distraction. I think the Mini F16 took 2 years from start to flight, and I'm still fooling with it. And cheap is right, not to add that I feel at this point in time that old stuff is still obtainable NIB and that won't last forever. Might not be able to do that in 10 - 20 years from now. I have a NIB Byron Originals F-16 I am planning on working on this winter.

Turbines? Yes I am sure one day but $10K on an airplane just seems ludicrous to me at the moment. Maybe when I grow up ;-)
Rick

BVM mixture control was the greatest thing ever invented back then. and dont forget Tom Cooks pitot pressure vent that mounted in the dynamax fan to pressure the tanks
DYNAMAX DUCTED FAN UNIT

In my experience (OS 91 with Ramtec fan) the plugs, lasted between 6 to 10 flights. I usually changed the throttle arm for something sturdier because the stock arm usually broke after some flight due to vibration. I also changed the red oring in the exhaust for viton orings) The mixture control is a must or you will be changing pistons and cylinder rather frequently.
OS 91 ran well with 5% nitro and 23% oil. If you increased nitro to 10% it ran ok, with slightly more power but it became more finicky.
Regards
Eduardo

Oh the memories... Broken throttle arms, burned out glow plugs, blown out tuned pipe o-rings, stripped starter wands, and my personal favorite the slimy forearm from reaching into the tailpipe to get the pipe hanger re-attached.
Boy we had a lot of fun! :cool: