IO-360 project

johneeb · Post by **johneeb** » Sat Aug 13, 2005 12:15 pm

Shawn,
XP-mods uses the original Hanlon Wilson (H&W) heat muffs. You do have to exchange the right side H&W for a left side H&W, or modify your right H&W, as the right side muff will not fit into XP's motor mount.

Building the new stacks was the most difficult part. We welded the riser pipes into the flanges at an angle to position the muff properly. In retrospect I would have done that differently leaving the flange at a right angle and used a bevel joint below the flange. I was able to make the riser pipes for the #1 & #6 cylinders this way using a double bevel joint. Cutting the bevels was easy using an adjustable metal chop saw.

The tail pipes are Bartones, which I had earlier installed and gotten field approval. We did have to fill them with sand and do some heating and bending to adapt them to the new angle of the heat muff exits.

One of the benifits of this installation is great cabin heat. I made a plate with two scat tube adapters that attaches to the back side of the original carburator air filter. I routed hoses from this new plate to each of the H&W heat muffs than routed two hoses out of the H&W to a made up colletor and on to the cabin heat inlet ( I have pictures if you want to see them ).

Got to go have breakfast at the local Steam Power show.

rudymantel · Post by **rudymantel** » Sat Aug 13, 2005 10:04 pm

That IO-360 is a sweet engine. I've owned and operated a Cessna 336 and several 337's and it's a very reliable, smooth running engine. On the Skymasters at least it's the easiest starting fuel injection engine, hot or cold. Just give it a shot of prime and it starts like a car. You'll love it !
Rudy

johneeb · Post by **johneeb** » Sat Apr 01, 2006 2:34 am

Shawn,
How are you coming on your project?

ak2711c · Post by **ak2711c** » Sat Apr 01, 2006 7:32 am

Hi John. Its funny that you ask. I just about a week ago got all of my $$$ in line to do the conversion. I have the STC Kit on order from XP mods, and I have all of my engine parts on order for the overhaul. I have recieved some of the parts but not enough to start assembly yet. I have a constant speed prop with only 180 hours on it that I horse traded from a buddy. It is none too soon ether my old engine is getting really tired.
Shawn

johneeb · Post by **johneeb** » Sat Apr 01, 2006 2:11 pm

Shawn,

Good to hear you are moving ahead with your conversion.

What changes do you have to make to convert your pusher engine to a puller?

What prop did you trade into? I am using a McCauley 2A34C203-C, it works great has a lot of thrust, although noisey at max RPM.

ak2711c · Post by **ak2711c** » Mon Apr 03, 2006 5:43 am

There actually aren't any changes to make to the engine. The front engine is the same as the rear. The IO-360-C is just certified for pusher or tractor. I am just going from memory on the prop but I believe it is a 2A34C201. It is an 86" prop right now though so I have to get it cut down. Seems a shame to cut it down but oh well.
Shawn

blueldr · Post by **blueldr** » Mon Apr 03, 2006 7:59 pm

Shawn,
Don't cut that prop down yet!
If you have the STC by XP Mods it calls for a 2A 34C 203 hub (If I remember correctly) and if you have to swap, it's probably worth more
while it's long. I'd leave it long anyway. Who's to know?

Post by **GAHorn** » Mon Apr 03, 2006 9:30 pm

Certification of aircraft/engine/prop combinations include minimum ground clearances. I recommend you follow the STC instructions. (Old P-51 pilots may not care about such matters tho'.)

johneeb · Post by **johneeb** » Mon Apr 03, 2006 10:28 pm

http://www.pponk.com/HTML%20PAGES/propcalc.html

Shawn,
Have you seen this WEB site? It belongs to P-Ponk and calculates prop tip speed as a function of the speed of sound. They make a point that the efficeincy of a prop goes down when the prop tip speed exceeds Mach .92. Your 86" prop will reach slightly over .92 at 2740 RPM with an air temperature of 59 degrees F (gets worse as the temp goes down and better as the temp goes up). If you intend to utilize 210 horsepower from your IO-360 you need 2800 RPM therefore by P-Ponk's formula below 84 degres F. you will need a shorter prop. Below is a quote from P-Ponk's web site.

P. Ponk Aviation
Propeller Efficiency Calculator

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Would you like to know how fast your propeller tips are traveling, how efficient your prop is at a particular RPM, and how much noise you are making? Enter some different combinations of prop diameter and RPM setting below to find out. Note: Ambient temperature is needed to determine the speed of sound for a particular day.

To produce maximum thrust at full power your tip speed should fall between .88 and .92 mach. To move between .88 and .92 mach usually takes a change of about 110 to 120 RPM. This of course varies depending on your particular propeller and the temperature.

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If your tip speed is less than .88 mach you should increase RPM to achieve maximum thrust. If your tip speed is greater than .92 mach you should reduce RPM to achieve maximum thrust. Do not exceed the published operating limitations of your engine or propeller.

Over .92 mach the airflow begins to detach from the propeller which decreases efficiency and dramatically increases noise. To improve performance and public relations you should consider reducing RPM so as to fall within the .88 to .92 mach range. Your propeller will be producing maximum thrust which is good for you, and less noise which is good for all of us.

blueldr · Post by **blueldr** » Tue Apr 04, 2006 2:12 am

Shawn,
Propeller ground clearance is not a problem with an eighty-six inch prop on a C-170, but noise sure is. The maximum diameter useable in standard atmosphere conditions at sea level with maximum power of 2800 RPM is 82 inches. This is, of course, variable with temperature, etc.
Slowing down the RPM will reduce the noise, but will also reduce the power.
However those "loooong" props will really suck you off the ground!

ak2711c · Post by **ak2711c** » Tue Apr 04, 2006 6:17 am

Yeah I couldn't remember what the STC said for which prop but I know this one matches. Also from a recient conversation with Tom at XP mods it sounds like he got some other props approved also. I am still waiting for my paper work to show up in the mail so I have not been able to see what the new props are yet. Prop clearance is deffinitely not an issue with my plane but last I checked I was limited to 82" on prop length. Maybe there are some provisions for longer props in the new STC.

Post by **GAHorn** » Tue Apr 04, 2006 4:54 pm

Certification regulations require a minimum ground clearance of 7" from prop tip to ground in the level attitude for tri-cycle gear aircraft, and 9" in the take-off attittude for conventional gear aircraft. If the landing gear is a leaf-spring gear, it must meet the clearance with a landing gear deflection of 1.5 G's.

blueldr · Post by **blueldr** » Tue Apr 04, 2006 5:32 pm

OK George!

So if the landing gear is the early original type and figuring a 1.5 "G" landing deflection, you're limited to a prop diameter, disregarding the STC, of perhaps 82 inches.
With the so called "Lady Legs" models, additional length could be accomodated due to the additional rigidity.
With the C-180 gear known as the "Lady Favorites", which are even longer and stiffer, considerably more bulk and length are available.
Depending on the circumstances, every little bit helps.

Post by **GAHorn** » Tue Apr 04, 2006 8:39 pm

blueldr wrote:OK George!

So if the landing gear is the early original type and figuring a 1.5 "G" landing deflection, you're limited to a prop diameter, disregarding the STC, of perhaps 82 inches.
With the so called "Lady Legs" models, additional length could be accomodated due to the additional rigidity.
With the C-180 gear known as the "Lady Favorites", which are even longer and stiffer, considerably more bulk and length are available.
Depending on the circumstances, every little bit helps.

I don't disagree with your thinking process, Dick. I just wouldn't want to be on the record for recommending changes to approved mods that weren't performed in accordance with the approved data. If a longer prop were approved with the co-installation of longer gear, then there'd certainly be less reason to shorten a prop if it were detrimental to performance. To arbitrarily make such changes without a basis of approval,...or to vary from STC instructions and just "keep it quiet" hoping no one might notice... does not take into consideration other important factors of legality and safety. (If a "little" torque is good... more isn't necessarily "better".)

ak2711c · Post by **ak2711c** » Wed Apr 05, 2006 6:10 am

I currently have 180 gear and 26" Gar Aero tires on my plane, and I have a set of 31" Alaska Bushwheels on order for it. So prop clearance is not an issue for my plane. I have no intention of running an illegal prop on my plane. My comment was just simply that it was a shame to have to cut down this prop. The 180's get a lot more thrust out of those longer props, but I will take what I can get.