danny_galaga

2 hours ago, skippydiesel said:

What  sort of aircraft did you say all this is going in?

 

I shudder to think what convoluted, hard to bleed, plumbing is required - how about some photos???

 

Was KISS part of the design philosophy?

 

If it works as you expect then all good.

 

I thought you mentioned a high wing STOL - not something that tight cowling, is usually associated with.

 

High performance WW2 aircarft with huge engines, in very tight cowlings, often had remote heat exchangers (under fuse, in/under wings, etc) - is your baby in this company?😈

 

I bought a kit, not based on 'oh, this has one too many oil coolers in it', but rather on it looking like it would be a fun plane to build. Any technical questions, you will really have to ask them. It is a Skyreach Bushcat. There are many KISS principles at play in this design, for instance TRIM and FLAPS are totally mechanical, not electric. No auto pilot. I selected a carby engine. And a single piece wooden propeller (although it turned out to be the wrong pitch, so maybe SOME complexity, ie ground adjustable, could have been handy)  If one wanted to totally keep to the KISS principle, one would buy a hang glider.

Attached, a good frontal picture of someones Bushcat, for your edification. Visible are the radiator, above it the first oil cooler and above the spinner the second oil cooler 😇 

Yeah, it's a funky design. Instead of one larger oil cooler, theres two smaller ones. The top one is in and out, which i.guess has the advantage of none of that hot air going over the engine. More likely it's designed that way to make the engine cowl quite a tight fitting affair. Witness for instance where oil coolers end up on WW2 aircraft 😇 

52 minutes ago, IBob said:

ICP use the bobbin type shock mounts, top and bottom. But they can separate: I replaced one recently but I think it was originally mounted in a stressed (not straight) manner.

 

 

 

My top oil cooler is mounted with these on the top of the engine. The bottom oil cooler and the radiator are just mounted directly to the bottom cowl. 

3 minutes ago, Freizeitpilot said:

Should I buy a single Bose replacement headset microphone foam windscreen from Aircraft Spruce for $22.95 + delivery or 10 non-genuine ones off Temu for $2.06 ??

Tough call 🤔

Yes OS is probably still the most popular 

43 minutes ago, facthunter said:

They wear out in the bore fairly quickly, But run well. Are they still made?  nev

No. But many engines (like my own childhood engine) hardly got any run time on them before being jammed in the back of a drawer. So quite a few near new ones pop up. They are popular for stunt because there's a certain speed you need to fly, any improvements on power are wasted in this case.  There's a few Ruskie and Ukrainian engines around too. 

A number of guys are running Fox 35s at the club 🙂

1 hour ago, skippydiesel said:

Very clever - the kit comes with a  a 25 MM ID hose adapter - not so many joins after all.

 

"........don't understand about having different radiators for aircraft with different performances....."

 

Its not a question of me not understanding that coolant radiators must be specified for diffrent engine sizes/applications, etc,  its wondering why your kit supplier sees fit to not use the Rotax OM Radiator,  that has been  developed for the engine and what seems to be satisfactory in a host of aircraft from low/slow to high speed, pushers and tractors. Nothing sinister or argumentative , just curious 😈

Id say you should email them, but they've gone broke in the meantime 😄

From the build manual. Doesn't look like that big a deal to me. And I still don't understand what YOU don't understand about having different radiators for aircraft with different performances. Its as if you couldn't see that maybe a radiator from a F1 car might not perform exactly the same in a LandCruiser 😇 

1 hour ago, skippydiesel said:

I have never suggested you (Zenith et al) are wrong, only that the approach is somewhat unconventional. I like unconventional, especially when it works. Despite this I am not a fan of "reinventing the wheel" for no apparent gain.

 

I still wonder at the choice, given the diffrent viscosities of oil & coolant (water) and I assume the Setrab heat exchanger has been optimised for oil (it looks like an oil cooler).

 

In addition, the Rotax 9 coolant system will have 25 mm OD hose connections , so at some point reducers will have to be fitted to get down to the Setrab inlet/outlet dimensions - added weight, more joins ????😈

The port size is 22mm, not as small as you are probably imagining 

1 hour ago, skippydiesel said:

Speculation: For Rotax 9 powered aircraft, high / low / rotating, the Rotax radiator is the norm - Your dual purpose oil/coolant, the exception. Nothing wrong with that of course😈

It's much the same size in the similarly performing zenith and savannah 701. What's your theory then, since the radiators are roughly the same price? Seems to me a slow aircraft could do with a larger radiator. Maybe you ought to write to the bush plane manufacturers and tell them they've been doing it all wrong 😇 

42 minutes ago, skippydiesel said:

Oh well there you go - I wonder why Rotax have stuck with the more conventional (PN 997083)  ???😈

 

I reckon maybe that one is for general low wing plane use, and slow draggy planes like mine are best off with something a bit different 

1 hour ago, 440032 said:

"Nope". Same wood bearers. I wanted the exhaust out underneath so model stays clean, and it does.

Damn, that's clever work 😎

Interesting news concerning the airline and possible culture/lack of training issues 

https://www.independent.co.uk/travel/news-and-advice/air-india-pilots-suspension-boeing-777-stall-warning-b2780259.html

2 hours ago, 440032 said:

51st year of flying control line.

Aeroflyte Kittyhawk with modified engine position.

Nice work rotating the motor. I've built it's brother the Spitfire, so I know it has hardwood engine bearers. I presume you left those out and fitted a radial mount to the firewall?

Look what I just won at the clubs annual dinner raffle ☺️

This kit is for carrier class. If you fly it in that class, it's 3 line control for throttle.

Incidentally, I've found the quickest and easiest way to keep my photos upright here is to just screenshot it 😁

Impressive, but the video to these old eyes is mostly looking at some lovely clouds and lots of humming ☺️

1 hour ago, skippydiesel said:

I didnt not suggest using an oil cooler, for a coolant radiator, would not work, only that it may not be the best design for the job.

 

Oil coolers usually ;

• Are of heavier construction, than needed for coolant - in aircraft all unnecessary weight is usually avoided
• Have smaller ID inlet/outlet pipes - this may result in the need for pipe reducers, more weight & complexity

 When perfectly satisfactory dedicated Radiators & Oil Coolers are available,  I wonder why you or is it the kit supplier, would choose to do this??😈

I didn't randomly choose that radiator.. people much smarter than me, aeronautical engineers, chose that part number. Now I look at it, it seems bigger than the standard Rotax jobby. Considering that it's a low n slow plane from a hot country, and the particular location of the radiator, I'm guessing they crunched some numbers on a variety of options and this one did the job for a reasonable price 😇 

1 hour ago, skippydiesel said:

Yes - as I acknowledged BUT how effective is the Setrab in BOTH roles???

 

Seems to me that if an oil cooler can be used as a coolant radiator,  then this would be common practise - last time I looked its not.

 

I would like to know the technical reasons why not.?????

 

I am sure there are Forum members who would be fare more qualified to debate this  than me😈

Right now I have to put tape on it to keep the temperature up. So I guess it's not too bad at its job 😇 

53 minutes ago, skippydiesel said:

There seems to be a small confusion in this thread between Radiators & Oil Coolers.

 

Radiator - Name commonly use for coolant heat exchanger

Oil Cooler  - Name commonly used for - you guessed it, oil heat exchanger.

 

In both cases they are air/liquid heat exchangers (there are liquid/liquid heat exchangers). 

Many similarities however, their design differences tend to reflect liquid viscosity and expected temperature & pressure ranges.

Not saying that the one heat exchanger design, could not be used for oil or coolant,  however I have never seen this and I would suggest that the targeted liquid is more likly to be efficiently cooled eg Danny-G's Setrab example looks to me to be an Oil Cooler., while Rodgerc's is a Coolant Radiator😈

In the case of my Setrab, it can be used for either. No confusion from me 😇 

Thats good news. That price seems quite reasonable, similar in price to Setrab. Mayb Rotax radiators are made by Setrab 😄

Ha. Setrab cost MORE! Mind you, i think its a bigger radiator. This is what goes in the Bushcat:

https://www.efisolutions.com.au/setrab-proline-std-oil-fluid-cooler-series-9-405mm~143016?srsltid=AfmBOoqZPRFVrt9dpFfaFCFrdlBTnnYo5pnc6ENs5a8rG0fEtEJMOTWS

For what it's worth, my Bushcat uses Setrab coolers, from Europe. I think you could probably get them from performance car shops. As far as I'm aware, there has been no issues in any Bushcat. They aren't dirt cheap, but $90 sounds TOO cheap for an aircraft. Not sure of specific prices but I bet Setrab are cheaper than something with a Rotax sticker on it 😁

51 minutes ago, Red said:

Getting back to Turbines Steam Turbines perform well in US Carriers but only practical because they have a nuclear reactor onboard to generate the heat to make steam.

Gas turbines directly fuelled with built in combustion chambers seem to have settled mainly into aviation use, I'm unsure if they still get used in some tanks and trains but they have in the past.

Compound Turbine/electric systems could still be practical in large trucks with room for the fuel in the trailer but emissions are just too High with common fuels...hydrogen perhaps?

Gas turbines are also used in electricity generation. 

1 hour ago, facthunter said:

Not IF Trump has any say in it. He's Drill baby, drill and Bye Bye to the EPA. Out of Paris agreement. EFF all of you. Nev

What ol' yam tits doesn't grasp is that corporations don't care. If it's beneficial to them, they'll develop it and sell it overseas. It doesn't HAVE to be bought by Americans...

On 26/06/2025 at 10:51 PM, Marty_d said:

Ok, I know it's not strictly an aircraft engine, but I found it informative. Also some motoring history I'd never heard of.

Six Decades Ago, General Motors Created A Ridiculous Twin Gas Turbine Semi-Truck That Looked Like A Moon Rover - The Autopian

WWW.THEAUTOPIAN.COM

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General Motors once tried to reinvent trucking. This is the GM Bison a wild moon rover-looking semi-truck with two turbine...

 

Why does this truck remind me of Moon Patrol?