Monnett Super Vee Conversion

[mredmond]

Wondering if anyone is using or know someone who is using a Monnett Super Vee Conversion with the prop extension cone. History and reliability of them. Thanks for the help.
mredmond

Edit: Fixed typo in title for efficient searching in the future - JL

 

[karmarepair]

All the early Sonerai used this type of extension with an outboard bearing, up to the first IILs, before the Econo Vee conversion was developed. Here's one on Blueberry:
http://www.totalracing.com/bluebery/motor.htm built by Ed Fisher!

SOMEONE, I think it was the Zoomy team, told me they did not like the mechanical design of this extension, and removed it. To get the prop in the right place with the much shorter prop hubs, a long spool extension was used. NOT a combination I like, but it worked, as long as the case was renewed every season, as it pounded out the center main bearing pretty badly.

 

[Raceair]

There was a small batch of inferior super vee shaft extensions that were prone to cracking at the keyway. After Charlie Terry had two failures with #14 'Beetlebomb', and Vance Graebner had one, and a couple others did too, Charlie had a batch of new ones made from a blueprint, I think, that was provided by John Monnett...I am unclear on that.....Blueberry's had not failed yet, but a new one was installed, I believe, by Charlie and Jim Vliet, who had bought #77 from me by then. The Super Vee extension is great, in my opinion, if it has the better shaft extension material. Don't remember if it was an alloy or heat treat problem, but the problem was short-lived, in the 1977-1979 era....Hopefully, any Super Vee shaft extensions out there today are of the superior material....Ed

 

[mredmond]

Thanks to everyone for their help. Do appreciate it.

 

[smoothmat]

I recently purchased a sonerai 2 from 1977 and it has a supervee prop hub.
The 76mm crank was changed out to a 74mm crank after a crack was discovers at the #1 bearing. The plane has not ran in 20 years now and i wish to put it back in service. Although the engine runs fine and everything works i am going to tear down the engine and take a look at all the internals.
The case has been align bored to .040 o/s
B/c the crank is only 74mm now it is reduced down to a 1800cc from 1850cc
I want more cc

Should i change the 88mm cyl to 92mm, crank from 74mm to 69mm, new cam = 1835cc
or
should i replace the crank for a new 76mm 4140 chromemoly forged steel and keep verything the same = 1850cc

other suggestions?

I don't want to out a upgrade to 2180cc. Eventually i want to purchse a new 2180cc from GPAS

 

[karmarepair]

New, bigger P&Cs will require case and head work. IF you go down that road, Go Big, IMHO - 94 mm.

Me, if everything checked out OK, I'd button her up and fly the existing configuration until the compression goes south, or the heads accumulate 250 hrs and need rebuilding, whichever comes first. I doubt you'll notice 50cc difference.

 

[smoothmat]

engine total time is 250hrs. i was thinking of purchasing some 042's anyways.


Is it possible to get a newer monnet prop hub these days. I read somewhere that at one time some fellows made some news ones with different material???

 

[Raceair]

Uh....You read that here, on this topic....scroll back and look at my early October post...The batch of prop flange extensions that was built has been distributed, many years ago. I don't know of anyone building new replacement parts for the Super Vee front end. I think that Charlie Terry originally got a Drawing from Monnett Experimental Aircraft, but I doubt anyone at Sonex, Ltd., is interested in producing new ones these days.....Ed

 

[Ronzie]

engine total time is 250hrs. i was thinking of purchasing some 042's anyways.


Is it possible to get a newer monnet prop hub these days. I read somewhere that at one time some fellows made some news ones with different material???

There's a Monnett prop flange/extension, with a good crankshaft attached, for sale here:
http://www.sonerai.net/CMS/index.php?option=com_jfusion&Itemid=180&jfile=index.php&topic=2040.msg13810#new

Thanks,
Ronzie
hoverhawk(at)hotmail.com

 

[Outlandar]

Hello mredmond

The first Super Vee hubs had a welded flange and there were cases of cracking at the weld. Then there were ones that had been made from a soft material and had problems at the keyway. Later hubs were harder and much more durable. In all cases it is mandatory that the hub runout be kept at a minimum. I believe John stopped making the SuperVee engine because of the time (expense) needed to install/true the hub and then shim the cone and then epoxy the cone mounting bolts.
BlueBerry's Super Vee hub had considerable problems. Charley replaced the key a number of times at the races, (I gave him with a key at Daytona 1989 after his hub became loose after qualifying.) Then Charley had some hubs made up and reliability improved. That version was damaged in the midair at the Myrtle Beach 1994 Championship race.
I was saving my Super Vee hub for my S-II and started to do a new hub with a tapered connection instead of the slip fit of the original. I still have this Super Vee hub/cone.

I am having problems with pictures, I will try to get them up later

Yours, Brian Dempsey

 

[Outlandar]

Hello mredmond

I was able to get a couple pictures in my gallery of the hub installed on an engine that were taken a few weeks ago. I will work on more pictures of the hub pieces as soon as can get computer problem resolved.

Yours, Brian Dempsey

 

[mredmond]

Hello Brian,
Thanks for the pictures, looks just like the one I have, and look forward to seeing the other pictures. I had purchased this S1 project about a year ago and some of it has been assembled already, such as the prop hub and the HAPI accessorie case. The prop hub has been shimmed, don't know if the bolts have been torqued properly or not. Any information out there on the instillation and torque values would be great. From the looks of the exhaust ports and the little I can see through the spark plug holes it looks like it has been overhauled. Currently installing an oil filter and cooler. I will try and get some pictures also on here. I do appreciate the input from everyone.
Thanks again
mredmond

 

[smoothmat]

that looks exactly like what i have. I will go to the shop tonight and take a few pics as well

 

[Outlandar]

"The prop hub has been shimmed, don't know if the bolts have been torqued properly or not."

Hello mredmond
I have the installation instructions somewhere. I will make it available when I find it or I will write it down from memory.
Yours, Brian Dempsey
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
"The plane has not ran in 20 years now and i wish to put it back in service. Although the engine runs fine and everything works i am going to tear down the engine and take a look at all the internals.
The case has been align bored to .040 o/s
B/c the crank is only 74mm now it is reduced down to a 1800cc from 1850cc
I want more cc
Should i change the 88mm cyl to 92mm, crank from 74mm to 69mm, new cam = 1835cc
or
should i replace the crank for a new 76mm 4140 chromemoly forged steel and keep verything the same = 1850cc
other suggestions?
I don't want to out a upgrade to 2180cc. Eventually i want to purchse a new 2180cc from GPAS"

Hello smoothmat
I think an engine tear down inspection is a wise move considering its' history. If you are planning to get a new large displacement GPAS engine it may be more cost efficient to freshen up your 1800 engine and fly it. The money that would be spent on enlarging this one would be a good start toward the new engine. Also the Super Vee hub has limited power transmission capability due to the crankshaft slip fit to hub connection. The S-II will fly fine on 1800 cc. All of the S-II's I have flown have had 1835 cc or less. If you find you need parts for the 1800 engine I think I have spares including a spare 88mm piston/cylinder kit.
Yours, Brian Dempsey

 

[Raceair]

Blueberry's Super Vee hub did NOT have 'considerable' problems. The FACTS are that Charlie Terry had 'considerable' problems with the Super Vee system on N14CT, #14, 'Beetlebomb' early in the Formula V history.
Blueberry did have one failure, with an owner, in New York. The engine and Super Vee extension had several hundred hours on it by then. As Charlie had obtained a batch of better shaft parts, Blueberry got one of those.
As well, the 'midair' at Myrtle Beach had nothing to do with a prop shaft, and should not have been even mentioned in this thread....I am getting tired of seeing the cheap shots at Blueberry , and like to stick to the facts.....Ed Fisher

 

[smoothmat]

Brian,

Thanks for the feed back. I appreciate it. I think that i am going to just tear down, inspect, re-assemble engine. I'll add new parts if needed. The first owner/builder (i am the 3rd) was an aircanada mechanic and did a very maticulous job on this plane. It won the monnet "Designers Award" at oshkosh in 78! as well as Grand Champion at EAAC Orilla in 78! There also was a cronilogical write up as the builder built this plane. It was featured in Canadian Homebuilt Aircraft. This plane has since been sitting in a show room for 25yrs. The only downside is that it one of those birds weighing in on the heavy side. That is why i was considering adding more displacement but i guess if i stay in the 1800s ther will only be a few hp difference.

 

[smoothmat]

I posted some pics of the monnet super vee prop hub extension. Looks like it is aluminum, and the hub is brass??

 

[Outlandar]

"I posted some pics of the monnet super vee prop hub extension. Looks like it is aluminum, and the hub is brass??"

Hello smoothmat

The cone is aluminum. The hub is steel. The color is due to the coating. I have added some hub pictures to my gallery that you may find interesting.

Brian Dempsey

 

[smoothmat]

I dug up the prop hub drawing from monnet exper aircraft. Drawing #2 it has all the parts and a diagram. i also have the original directions on how to install the hub. I am going to scan and post them tomorrow.

 

[mredmond]

Thanks for going the extra mile in getting the installation instructiuons and posting them, really do appreciate it. I look forward to looking them over and getting a better understanding of the conversion.

mredmond