MB 5 Replica

[Gregory]

... is the CA15? Could you please enlighten me?

Gregory

[JDK]

Gregory,
I'm shocked! The Commonwealth Aircraft Corporation CA-15 was a potentially superb fighter, but the war ended before it was ready. Like the MB-5 it looked like a beefy P-51D, but was quite a bit bigger - and, if you believe the contemporary newspaper reposts very fast... Have a google for some pics.
Yours in Colonial Aviation,

[Gregory]

JDK

I went, I googled and I found. Now I see the light. What had thrown me off was Setter's mention of a big radial, which threw me into Boomerang/Wirraway mode.

By the way, what colonial aviation are we talking about? Ancient Roman colonies only had elephants, chariots and the like. We made darn sure they never developed serious technology. You guys gave your colonials free rein and ... they took you over! One of these days the IWM will be renamed the Republican Freedom Museum ... Wouldn't need to change the exhibits much, either!

Just my 0.02 Euro of attempted humo(u)r.

Gregory

[JDK]

Ahhh.

As an Australian resident in England (and married to a Canadian) I've been trying to civilise the natives, but I have to admit it's a lost cause.

And no evidence of Roman aviation doesn't mean there wasn't any; we all know of the 'armoured tortose' where they formed a block with shields. The lesser known 'ancient Roc' was where they all jumped on the enemy from a great height...

Back on topic, there's a great theme of 'fighter /trainers for W.W.II '46+':
CA15, MB-5, Fiat G-59, Bearcat, Tigercat, Sea Fury, Hornet, etc...

Cheers!

[Gregory]

I thought I saw an Oz accent in your writing. Don't ask how.

The Italians lacked the high powered engines to play in the league you mentioned.

I think that Mr Gabrielli is chuckling in his grave, seeing his tame G.59 compared with the mighty Bearcat. Now, the DB-603 powered G.56 and the A.82 radial-engined G.57 might have come closer, but somehow I remain skeptical.

Something which never flew, but would have been great, was the Merlin-engined C.205: basically a P-51D nose grafted onto the classic Macchi fuselage. Now, if I saw that project through, would it be a late prototype, a replica or the rape of a rare original airframe?

Or the Namcu twin-Merlin fighter designed by Pallavicino in Argentina just after the war, drawing upon his wartime experience ... A sort of Hornet, if anything sleeker and more elegant. And sadly, extinct through remaining unbuilt ...

Gregory

[bdk]

Its a nice over-size kit plane but I can't see the FAA given it a Flight Cert.

Whaaaa? It's a homebuilt... Just plain experimenal.

[Jeffrey]

JDK

I went, I googled and I found. Now I see the light. What had thrown me off was Setter's mention of a big radial, which threw me into Boomerang/Wirraway mode.

Gregory

The CA-15 was actually meant to have a big radial to start with, from memory. if I can find my book on it here somewhere I could even tell you what sort. I do know though it went through a number of different incarnations, about 3 engine variations from memory as different ones became unavailable or development of them finished or something, as it was on the drawing boards from just after the finish of work on the boomerang and was originally meant to be an indigenous true fighter in the way that the boomerang was meant to be but didn't quite make it.

having talked to the guy who flew most of the test flights in the CA-15 he reckoned that the reports in the news papers were accurate enough. He also flew a mustang and said it was close but when compared side by side the CA-15 when light on fuel had it beaten for speed, according to him.

[dj51d]

The CA-15 was actually meant to have a big radial to start with, from memory. if I can find my book on it here somewhere I could even tell you what sort.

Unless my memory has failed me, it was the R-2800.

[JohnH]

Hi All,

Just a thought does anyone really want to see if someone will get Killed in this thing, remember the Super T-6 that had the 4350( I think) build on with extend wings and rebuild Fusg. it did two flights both almost ended in tragedy.

Its a nice over-size kit plane but I can't see the FAA given it a Flight Cert.

Cheers RR

I really hate to speak in public negative about this but I was looking at this on Sunday and saying the same thing to a friend. Having just read that Dreadnought recieved a larger tail when it got the 4360, isn't the tail on this thing too small also?

John

[JohnH]

Here's a couple of pics, don't have a better angle.

John



[/img]

[Randy Haskin]

remember the Super T-6 that had the 4350( I think) build on with extend wings and rebuild Fusg. it did two flights both almost ended in tragedy.

Are you referring to "Wildfire"? It's baaaaaack!

http://www.wildfireairracing.com/

There was a big discussion at AAFO.com about 6 or 7 months ago about Wildfire. Apparently the reports of the unsafe flight back in the 80s were drastically overblown. There is a very good discussion of this here: http://www.wildfireairracing.com/ask.htm. More to be written on this story in the near future since they are working on it more aggresively again. Maybe it'll flop, maybe not.

Its a nice over-size kit plane but I can't see the FAA given it a Flight Cert.

Back to the MB-5...it's experiemental, so what exactly does the FAA need to certifly??

Last edited by Randy Haskin on Fri Sep 24, 2004 5:14 pm, edited 1 time in total.

[Randy Haskin]

I really hate to speak in public negative about this but I was looking at this on Sunday and saying the same thing to a friend. Having just read that Dreadnought recieved a larger tail when it got the 4360, isn't the tail on this thing too small also?

Those contra-rotating props do a nice job of countering the torque, so probably not.

[bdk]

Those contra-rotating props do a nice job of countering the torque, so probably not.

Sorry, the contra-rotating prop doesn't change the need for a larger vertical stabilizer.

Given an already flying airplane, a contra-rotating prop has a greater polar moment of inertia due to the increased blade area/mass. This requires a larger vertical stabilizer.

In Dreadnought's case, the prop is quite a bit farther forward than on a stock Sea Fury since the engine is longer. Since the polar moment of inertia acts on a longer moment arm, a larger vertical stabilizer is required to maintain the same stability. On the Super Corsair, the R-4360 was moved back quite a bit since the R-4360 has radially positioned accessories (like the Centaurus) while the R-2800 has them positioned behind the engine parallel to the crankshaft centerline. This kept the Super Corsair prop roughly in the same place.

Torque and P-Factor are neutralized with a contra-rotating prop however.

Griffon Spitfires (5-bladed props) cannot use full throttle on takeoff because they can't maintain directional control. Vertical stabilizer lift is not adequate at low speeds. Lift is a function of vertical stabilizer area, rudder size, and rudder deflection (and airspeed obviously).

In conclusion, the need for vertical stabilizer area depends on the polar moment of inertia of the prop and the prop's moment arm. That's to maintain adequate yaw stability. This can be balanced through the use of a larger area or a longer moment arm for the stabilizer. I think you'll find a longer tail on the MB-5 replica than on a Mustang.

Now a few comments about the MB-5 replica...

I watched John Marlin lay out the framework for the MB-5 replica in Chino. He kept it as close to original as he could given the use of Mustang parts and no engineering drawings. He had plenty of photos and other data to do the design, so I suspect that it is closer than some suspect. He retired from Rockwell (now Boeing) in the blueprint shop, so he had access to all the equipment required to scale up drawings and photos to the required size. He also enlisted the help of Bruce Boland as I recall for the basic aerodynamic design (i.e. stability and control calculations). This is a high powered homebuilt. I'm sure John will use a qualified test pilot for the initial flights and will not do the actual race piloting himself (at least he never did with his Mustang).

[Elwyn]

"Are you referring to "Wildfire"? It's baaaaaack!"

http://www.wildfireairracing.com/

Their 3 view certainly gives a better impression of the layout. I didn't realize the wings were so stubby or the fuselage was quite that small compared to the engine. The plane looks shorter in the 3-view or maybe the cowl is too wide. Just doesn't seem to match the photo exactly.This things looks like it will have tons of torque to counteract! Sure is an interesting looking beastie.

Last edited by Elwyn on Fri Sep 24, 2004 10:54 pm, edited 1 time in total.

[bdk]

Sure is an interesting looking beastie.

Elwyn, you are far too kind in your description of this aircraft's appearance!

I saw this aircraft nearly 25 years ago in Van Nuys when it had the "bundle of snakes" tuned exhaust system.

Supposedly these guys know what they are doing, but some airplanes that look good don't fly well- far fewer fly well that don't look good!

It certainly wins the award for the longest under construction Reno racer though.