# Rudy Kouhoupt 5 cylinder radial

### Help Support HMEM:

#### lensman57

##### Well-Known Member
Hi,

I wonder if anyone of you gentlemen has built the above engine?

I am studying the plans for now, as printed in the volume 4 of the shop wisdom of Rudy kouhoupt and I am having difficulty figuring out all the arrangement of the main valve, item 25 in his drawings.

Any help would be welcome.

Many thanks and regards,

A.G

#### Don1966

##### Senior Member
A.G. I think what is throwing you off is the inlet and exhaust cavity. If you look at the first drawing it starts with B-B inlet groove & cavity at 18degrees, this intersects at .38 diameter at B of the center drawing. Look at C-C inlet cavity /exhaust cavity it intersects at C of the middle drawing at a 18 degree flat and a staight down exhaust cavity both offset by .062. They are both extensions of the middle drawing showing the flats that have to be cut at B and C. Look closely at photo 28 and 29 you will see the grooves cut at these intersections. Hope this helps.

Don

#### lensman57

##### Well-Known Member
Hi Don,

Thank you for your reply, I am still a bit confused as to the location of the flats that are cut at 18 Degrees to the reference line. Am I correct to say that the point of cut starts from 0.062 above the centre line and at 18 degress across both the groove and the flange? The exhaust groove seems to be more straight forward starting and finishing 0.062 below the centre line on each side.

A.G

#### Don1966

##### Senior Member
A.G. What the drawing is doing is showing B-B and C-C in a cross section view of the middle drawing so you can visualize the grooves. B-B is a flat at B starting at 18 degrees from center line. C-C are the flats at C of the middle drawing 18 degrees and .062 from the centerline for the inlet cavity and .062 from center line straight down for the exhaust cavity. You can see a square space missing in the middle drawing at C for the exhaust cavity. The flange has only a .188 central groove cut in it. Remember the cavities has to meet with the center drilled hole for the air to get in and out.

Don

#### Vaughn

##### New Member
A.G., I built the Kouhoupt radial several years ago. It runs very well and once you get the drawings straight in your mind it is a relatively easy build. If I can be of any help let me know. When you run it with a prop it sounds like an aircraft engine.

#### lensman57

##### Well-Known Member
A.G. What the drawing is doing is showing B-B and C-C in a cross section view of the middle drawing so you can visualize the grooves. B-B is a flat at B starting at 18 degrees from center line. C-C are the flats at C of the middle drawing 18 degrees and .062 from the centerline for the inlet cavity and .062 from center line straight down for the exhaust cavity. You can see a square space missing in the middle drawing at C for the exhaust cavity. The flange has only a .188 central groove cut in it. Remember the cavities has to meet with the center drilled hole for the air to get in and out.

Don
Hi Don,

Thanks yet again for your reply and help. I can visualise the exhaust cavity to be machined at the indicated width to end up at 0.062 below the centreline to provide the necessary break into the axial cavity for the air flow. Am I right to assume that the two 18 degrees cuts are actually one and the same but with one cut intersecting the inlet groove but not breaking into the axial cavity?
I maybe making things more complicated for myself but I think that I have got it right now.

Many thanks and regards,

A.G

#### lensman57

##### Well-Known Member
A.G., I built the Kouhoupt radial several years ago. It runs very well and once you get the drawings straight in your mind it is a relatively easy build. If I can be of any help let me know. When you run it with a prop it sounds like an aircraft engine.
Hi,

Thanks for your reply. The promised sound of this engine is one of the reasons that I want to build it, I hope that I succeed once I hve got the plans in my head.

Regards,

A.G

#### Don1966

##### Senior Member
Hi Don,

Am I right to assume that the two 18 degrees cuts are actually one and the same but with one cut intersecting the inlet groove but not breaking into the axial cavity?

A.G
A.G. You now have it under control, you are correct.

Don

#### lensman57

##### Well-Known Member
Hi,

Thanks to all who replied with their tips and help. No doubt I shall be back for more advice once the build gets going. I have already ordered the 2.5" Dia 6082 and some 2014 for the rods and cylinders.

Regards,

A.G