|
The most disappointing thing about this thread is that they never built a production radial car engine. But radials were fitted to a few road vehicles......... Looks like a corn cob in this monstrosity: https://i.pinimg.com/originals/f8/7c...a0f4cd3604.jpg |
The problem is the duty cycle. Not necessarily for the crank and bearings, but for all the other junk that hangs off the engine. Then you have another fundamental problem. The electrical system for these engines must be “on” all the time unlike a magneto ignition. The injected Rotax 912 iS requires 7 switches to control it with some hope of failing safely. - Two ECU, Two fuel pumps, two alternators with failover logic dual injectors for each cylinder and dual ignition That might give some of you pause for thought. If conversion was that simple, wouldn’t everyone be doing it? |
The gasoline powered Sherman tanks were nicknamed “Ronsons”. |
|
Don't let this distract you from the fact that Hector is gonna be running 3 Honda Civic's with spoon engines. On top of that he just came into Harry's and ordered 3 t66 turbo's with NOS's and a Motec System Exhaust. |
Fully sick Bro! |
Originally Posted by Pinky the pilot
(Post 10457030)
I seem to remember that the 'autotug' was touted by GFA to be really something, but suddenly all development ceased and the project stopped with just the one example.
kaz3g; You got any info on just what transpired with that project? And why it has not proceeded? Because, over many years, CAA/CASA stalled the "auto tug" program. Why?? Because they could, despite US experience. There are thousands of aircraft flying behind "auto" engines, ranging from certified engines (many based on a Mercedes alloy block) through many V-8 powered smaller ag. aircraft in US, and the largest number in Experimental" aircraft. There are some "interesting" engineering issues, particularly engines based on the Chev. "small block", these are well known and understood. For those of you pontificating on proposition of potential propeller problems --- what, in heaven's name do you think reduction gears/drives are for?? Tootle pip!! PS: Alvis radials were extensively used in military vehicles, plenty of boats with Merlin (Meteor) and Allison V-12s. |
"For those of you pontificating on proposition of potential propeller problems --- what, in heaven's name do you think reduction gears/drives are for??"
Of course there are reduction drives on many aircraft engines Leadsled, that goes without saying. Point is, many look to auto conversions due to the affordability factor, without considering the need for reduction. A planetary reduction like on a PT6 or double helical reduction like on a Merlin adds cost. Company I worked for tried it, sunk a lot into it and ultimately failed to achieve a reliable cost effective auto conversion that suited their operation. Which was a shame, as they put quite some effort into it. |
A planetary reduction like on a PT6 or double helical reduction like on a Merlin Or is it a case of 6 of one and half a dozen of the other?:confused: Currawong; Any idea what was used in various other engines such as the big radials? And BTW, what was used in the GTSIOs used in the C404/421 series? |
Currawong,
The only Merlin/Griffon reduction gearboxes I have seen/played with have been straight cut spur gears. A major source of noise. Tootle pip!! PS: The pom's ability to cut helical gears, let alone hypoid bevels or double helical gears has always been rather marginal, and in the mid-1930's --- effectively non-existent. |
Originally Posted by LeadSled
(Post 10458673)
Currawong,
PS: The pom's ability to cut helical gears, let alone hypoid bevels or double helical gears has always been rather marginal, and in the mid-1930's --- effectively non-existent. |
Not a proven option yet, but Raptor Aircraft (a brand new kit aircraft designed and being built by an Aussie in the USA) has a 3.0 litre turbo Diesel which is estimated to put out 350 HP.
Raptor Aircraft Home These VW/ Audi diesels can be truly disruptive - they can run on Jet A1 and their SFC is half that of your air cooled flat sixes. Fingers crossed they can deliver even half of their promise. |
Originally Posted by lucille
(Post 10458739)
These VW/ Audi diesels can be truly disruptive - they can run on Jet A1 and their SFC is half that of your air cooled flat sixes.
. |
Originally Posted by Andy_RR
(Post 10458763)
No they're not. If you're lucky they'll be at or around 220g/kWh. A IO-550 is easily good for 250g/kWh and probably less when things are leaned properly - maybe closer to 235...
https://en.m.wikipedia.org/wiki/Brak...el_consumption Ps.. I tried to look for IO-550 BSFC numbers.. do you have a link? |
What “would be” converters don’t understand is that there are large and quite complex torque waves traveling up and down the crankshaft. These either get reflected, transmitted or damped at the ends. The engine designers take this into consideration but if converters mess with the dynamics then you can get weird and wonderful effects. Examples: rotax explaining what will happen if the engine is run without a propeller, the Jabiru flywheel attachment saga, various prohibitions on rpm ranges and so on. Even the big radials had issues: https://www.scribd.com/document/3256...800-Crankshaft |
Andy RR,
I did say marginal. Could you, perhaps, guess why RR Cars used diffs. imported from USA (GM) from about 1952 ---- sorry for the minor thread drift. I loved the example illustrated ---- a truly terrible gearbox, base don my experience rebuilding same many moons ago. Tootle pip!! |
I agree with Leadsled. There are few manufacturers in the world even today who routinely produce AGMA Class 1 gears for aircraft service. It used to be a black art - very, very skilled tradesmen were needed to set up and run the machines - which were Gleason gear hobbing machines, ANCA tool and cutter grinders and CMM’s. These days there are gear measuring software packages for the CMM’s and they integrate directly with CNC gear hobbers. But to my knowledge, now probably out of date, it is still a black art and the mating gears have to be matched as a set. Each gear is still slightly different and you need to “tune” the hobs and grinders based on the results of your CMM analysis. As for automotive and industrial gears - easy peasy because they ain’t Class 1. Also be aware that turbines don’t (I think) produce the torque pulses piston engines do. |
Originally Posted by nomorecatering
(Post 10457660)
|
Originally Posted by lucille
(Post 10459189)
I stand corrected. OK, not twice. But significantly better. The only figure I can find is for a 2007 BMW diesel of 198 g/KWh. VW have since improved their efficiency. cy. You only have to look at their automotive consumptions to get an intuitive feel. https://en.m.wikipedia.org/wiki/Brak...el_consumption Ps.. I tried to look for IO-550 BSFC numbers.. do you have a link? It quotes a 0.385 lb/hp.h which is 234g/kW.h although it may have got the best economy and best power figures switched on page 3. These numbers are, however, typical of what I've seen quoted around the traps for many years. As far as BMW diesels doing 198g/kW.h that's a very best-point number and there would be some celebration in the engineering office about it. Some of the old VW PD diesels are sub-200 but it's quite difficult to do and even more difficult to spread out across a useable area. The fuel consumption you see in the day-to-day use of a car is waaaay worse than these numbers, especially on a gasoline engine. If you could cruise at a steady 100km/h at 200g/kWh in a modern car you'd be seeing 3.5-3.8L/100km That's not typical of anything I know of. |
My Austin 7 had the 3speed crash box on a ‘27 magneto ignition engine with updraft Solex I later fitted a ‘36 coil ignition with 4 speed box fitted with a remote gear stick. The block was ported and polished, polished crank, Twin side draft Solex’s and extractors. felt like it was fast ☺️ Kaz |
| All times are GMT. The time now is 12:32. |
Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.