Hi Cruise Aeromatic

G

guzziduck

New member
What is involved in putting a hi cruise Aeromatic prop on a 165 Franklin, and is it worth the extra complication compared to a standard Aeromatic . Thanks, Richard
 
Richard, I am sure that Kent Tarver will give a much better explanation than I can, but since I own the original Koppers Aeromatic Bellanca and have read the manual many times, I will give it a try. The Hi Cruise in Aeromatic doesnt stand for hi speed , but for hi alltitude. It is an oil control to flatten the pitch of the prop when you start to loose RPM from the loss of manifold pressure as you climb. When you loose RPM you loose horsepower and even with low manifold pressure you will gain HP if the pitch is lowered to gain RPM. The actual mounting is not much different than the regular Aeromatic. Just remove the 1/4 inch pipe plug from the center of your crankshaft to let the oil flow to the prop and mount a valve on the forward left hand side of the 165 and run a cable to control the valve. Kent has the original Koppers co. instructions. If you commute between Denver and San Diego the Hi Cruise would be worth it, but most people dont have great changes in alltitude. NOW, in the real world; the only people that I have talked to that have Hi Cruise props on Bellancas use them to go above red line on take off for the extra HP, and then pull the control back to use the prop as a standard Aeromatic. Ask how your IA likes that idea?___ I have most likely shot myself in the wallet, since I have a Hi Cruise for sale, but I think they are only needed in specific conditions. ___ Some one pitch in and say if I am all wet on my information.____Grant.
 
Hi Grant, Thanks for the reply. My main question on the hi cruise is,how does the oil get from the engine, through the valve and then back to the prop? I am concerned about creating (more) oil leaks and other complications. The reason I've been looking at Aeromatics is I would like to get better climb performance without giving up top speed, and some, though not all, seem to feel this is the best way to go.The Hi Cruise variant seems appealing to me because I believe that it would allow me to count time in the Cruisair as complex time with the idea of possibly getting a comercial licence. Thanks,Richard
 
Richard, the front main bearing surface on a 165 crank has 1 more hole in it than a 150 crank which allows pressure oil to flow back into the center of the hollow crank. The 165 crank has a plug in the end(about 1.25 inch with a small pipe plug in the center of that plug) that contains the oil. The valve that controls this oil is on the front left of the engine, just above the motor mount. The valve replaces a plate that covers the oil holes on all 165s. Probably have to pull the nose bowl to install the valve. To mount the Hi Cruise you pull the small plug and bolt the prop on as normal (I assume a gasket or some type of sealer is used). The prop itself is just a standard Aeromatic with a hole drilled and tapped into the base, and a small pipe running outside of the hub to a hydraulic actuator on the front of the hub that flattens the pitch when oil pressure is put to it. As far as leaks go, the valve mounting requires a gasket, but then so does the block off plate that you replace, and the prop to crank mating surfaces would have to be good and be sealed with a gasket or compound . The small pipe running to the actuator could develop a leak but you would pick that up when you pulled the spinner every 25 hours to check the oil in the hub.The only complaint I have heard is that if the O rings in the actuator leak it could lock the pitch one way or the other. Remember that the pressure engine oil does not enter the hub, it only works the actuator. If Kent has actuators available he can modify any Aeromatic to a Hi Cruise. As far as my Hi Cruise goes, I want to pull the blades and check bolts before I set a price. Give me a call anyway , and we can chat.____Grant 707-928-5538. West Coast times.
 
Hi Grant, So is the valve that controls the oil Franklin specific? I have spoken with Tarver about these props, and the hard part is finding an oil control valve he told me. The prop that got me thinking is listed on Barnstormers with a valve and spinners, for an 8 bolt continental though. The oil control valve that is shown in the ad appears to use three external lines and may not be appicable to the Franklin engine. Kent did not know where to find any other valves and this may be a real problem. Have you got a valve for yours? I give you a call, hopefully tonight. Thanks, Richard
 
I took a look at the Hi Cruise on Barnstormers, and those are not the correct blades for the Cruisair, nor is the valve for a Franklin. It is a very nice looking prop but would probably require new Blades to be legal on a Bellanca. Bernie from Down Under sent his Aeromatic to Kent and discovered he had the wrong blades, so Kent made him a new set. I have the correct valve for my prop and the little bracket that guides the cable. The price of a used Aeromatic is almost 100% based on the condition of the blades. Not the cosmetics, but the lag bolts. Make any purchase contingent on Kent saying the blades are serviceable. New blades are pricey. Give me a call.____Grant.
 
$3,500 to check out my Aeromatic and install new blades. But well worth it because I know that my prop is safe and won't throw a blade.
Gary
 
Not all 165 have that special front bearing, Some were built with the other style. You may buy the prop and then find out it won't work. You can pull the small plate off where the control goes and take the plug out of the crank and see if you can blow air through the crank. If not get a regular Aeromatic. I still have a good prop with good blade that came off of my Cruise Air.
 
Hi Greg, This is over my head now, but I will ask the question anyway. Would you have to turn the crank a full revolution while the air pressure was on it, so that the hole in the bearing and the hole in the crank had a chance to line up? Or would the few thousands of clearance between the bearing and crank allow enough air thru to do the test? I love learning from this forum. I would never even have thought to do this test._____Grant.
 
I pulled the blades on the Hi Cruise today, and all of the bolts look good. I didnt do the torque test since I understand that Kent pulls and examines all of the lag bolts. I am sure the hub will need an overhaul from sitting for many years. I will talk to kent tomorrow._____Grant.
 
I answered my own question about the air being able to blow through the crank. I went and looked at a proper 165 front bearing and it has the extra hole and an oil groove all the way around. No need to rotate the prop to see if air will go through. I also looked at the oil control valve and it is a Sensenich part number F2164. I just called Sensenich, and they said they sold off all the remaining parts for the Skyblade years ago. The Skyblade and the Aeromatic Hi Cruise used the same basic oil control system.______Grant.
 
Got to the airport yesterday, pulled the spinner and sure enough there was the plug I didn't remember. Will check for connection to control valve at annual, soon as the mechanic can accomodate it. Richard
 
Richard, I sent the blades to Kent Tarver and the lag bolts tested good. The blades will need a coat of paint,but that should be all. Of course the hub will need at least a reseal , and probably an overhaul. I just ran across an adjustment instruction for the Hi Cruise that was more legible than my old one and it says (cruise RPM may be selected at the pilots discretion) .That is more adjustable than I thought. Give me a call if you would like a copy of the instructions. I am going to put the prop on Barnstormers when I get back from a trip next week._____Grant.
 
You must log in or register to reply here.
Back
Top