franchi

Hi All:

One of my favourite engines is an older MVVS D7. I have had it on a Dumas Tom Tom for about 35 years. This is a great sport engine as it starts so easily and runs very well!

Anybody out there ever use one of these? If so, what are your impressions of this engine?

Tia,

Franchi

AMB

WHAT IS DIFFERENCE BETWEEN THIS ( D-7) AND THE 3022dfsr 15 MVVS DIESEL?? Martin

PWF63

Hi Martin
I can answer this.
See attached 3 photos of a MVVS D7. Thay were tha same vintage as the Super Tigre G20 deisels.
My only experience with both engines were as racing engines. I used a D& in Australian Goodyear racing for a few years and if anything.
I got better results with it than the Suer Tigre's.
I also agree that both engines make great sport engines.
Whilst we would run the G20's and D7's in TR Rat Race and Goodyear model on 7x6, 7x7 or 7x8 glass props running hard,
using them as a sports engine on larger props, they should last a lifetime on the right fuel.
Hope this helps

Fredo

AMB

THX Fredo the only rear exhaust 15 I have is an irvine do not think to many out there started life as a glow and you can see the top of head was machined down from a car head
guess Irvines try in the car thing , and evolved into this fitted with a diesel head by A.J. Coholic . I have not really played with it yet martin

they made up a custom prop nut/spinner since shaft as stock too short to mount a prop

AMB

see above post irvine 15 rear exhaust

Diesel Die-hard

I used a D7 for some years as my main combat 15.  A really great engine - started well and ran like Jack the Bear by the standards of the day.  Also stayed together, although it needed a new rod once in a while. More recently, the engine got banned under our area vintage diesel combat rules (it would simply bury any PAW or Oliver), but I still have an example in an own-design wing which I fly once in a while just to fly for fun.  It still goes as well as ever and runs great! 

fiery

My Feedback: (2)

Here is my RE/RV example (not D7).

The 4.5 mm bore venturi is too large to permit reliable use on suction.

Is there a scource for the narrower bore venturi insert?

ffkiwi

Interesting vertical protruberances on the front bearing housing fiery-I wonder what they're intended for? ....attaching a cowl or front cone a la Bugl to perhaps....?

ChrisM
'ffkiwi'

qazimoto

My Feedback: (1)

Silly idea so deleted!

paw080

Hi D-D, Decades ago when Bare and I were flying 80 mph Combat, we were campaigning

.15 diesel powered models. We both had MVVS 2.5 diesels and we were getting 81-83mph

on 60' X .015" lines, using our fuel mix and 8 X 6" props. This was without towing a streamer.

That of course posed a problem; so Bare built larger area models and I switched to a reworked

ST RV .15 diesel that pulled my same model 79 mph, sans streamer.

Tony

AMB

interesting engine, guess this was Irvines attempt at a car engine , excellent engine data on it 4000 to 30000 rpm 0.9HP, they never got any market penetration so they machined down
the top the of the car head for aircraft use, made a extended spinner nut so a prop could be mounted I think very few made picked up from Just Engines UK around 2005
I do have the tuned pipe for it also will do a serious bench test with a few props for a 15 an 8x4 or 5 as a start
the Diesel head was made by A.J.Coholic will keep the group posted on the results it is a twin BB. do not believe many around martin

Irvine 15XR

BrightGarden

This thread hasn't seen updates in over two years but if anyone is listening, I am looking for some help with a D7, new-to-me, that I simply cannot get started. I haven't performed any disassembly yet but i figure there is nothing more I can do on the exterior of the engine.

The venturi seems really wide to me, but I didn't question it. There was mention above of venturis being so big they don't create enough suction - that got my attention.

Next stop is checking out the NVA which seems to work just fine but I won't know unless I check it out.

qazimoto

My Feedback: (1)

Assuming that you don't have a through venturi NVA.

Then the venturi hole for c/l stunt type uses should be about 3.2mm or 1/8" plus or minus a tad.

A Cox TD 049/051 banjo/venturi works just fine in most .15 size diesels.

A good way to test the hole size is to insert the twist drill that just fits.

BrightGarden

Hi Q - Thanks for all the help with this. Hopefully, the rotated cylinder insert will do the trick with making this work. Interesting about the TD similarities - and we determined my version of the D7 does have the through-venturi NVA, looking forward to seeing how this all works out tomorrow on the bench.
Then, to mount it into something interesting and worthy.

Best, Peter G.

qazimoto

My Feedback: (1)

The TD venturi doesn't fit direct;y. You would have to fit a Delrin or Aluminium alloy plug into the D7 venturi, and it would have to be tapped 1/4" x 32 UNEF. It can be retained by a clinch bolt through the other venturi hole.

A quick and dirty way to reduce the hole size in a through NVA is to whittle down a bit of wood and jam it into one side of the venturi hole. A club mate did this to one of his PAW diesels and since it worked he still uses it that way years later.