About a year ago I talked about a letter I had run across on the Sensenich web site that stated that any wood Sensenich prop could be replaced with an equivalent Sensenich metal prop. I told a friend about it and he just recently used that letter to get approval for a Sensenich metal prop on his 150 Franklin powered Cruisair. I called the IA that got the approval (the same IA that does my annual) and he said that the Sacramento Fisdo argued about it , and then said OK , since it was a factory letter. They didnt even require a field approval. He just did a 337 that refered to the letter and a new w&b. I can no longer find that letter on the web site, but as soon as my friend gets back from Oshkosh I will get a copy of the 337 and the original letter. It might make it easier for the next guy._____Grant.
Sensenich metal prop on Cruisair.
- Thread starter gjordan
- Start date
Larry Lowenkron
Member
Way to go Grant! Was that Tom's plane? We really do need that letter/337 for so many Cruisairs.
jeffw
New member
when i purchased my 14-13-2 in 1991 the plane had a sensenich metal prop on it. it did well for me until i just couldn't live anymore until i put an aeromatic on the plane. they are beautiful and i wanted a better climb.
the sensenich prop allowed me to run at a higher rpm than the aeromatic so i got a higher cruise airspeed with the metal. but, the aeromatic lets the engine run up about 200 rpm more on take-off/climb out with slightly better vert ft/min.
the aeromatic might give me a higher cruise airspeed if i had some adjustments made to it that would require me sending it back to kent, but that's not guaranteed and the expense/hassle/possible shipping damage keep me from doing that.
I had the metal prop repitched in 1998 to its max climb limit, and it still gave me about 12 - 15 knots higher cruise AS than the aeromatic (but again, i was running it at 2700-2750 rpm). the aeromatic on a 165 hp franklin is limited to 2450 rpm cruise, hence the slower AS.
the sensenich prop allowed me to run at a higher rpm than the aeromatic so i got a higher cruise airspeed with the metal. but, the aeromatic lets the engine run up about 200 rpm more on take-off/climb out with slightly better vert ft/min.
the aeromatic might give me a higher cruise airspeed if i had some adjustments made to it that would require me sending it back to kent, but that's not guaranteed and the expense/hassle/possible shipping damage keep me from doing that.
I had the metal prop repitched in 1998 to its max climb limit, and it still gave me about 12 - 15 knots higher cruise AS than the aeromatic (but again, i was running it at 2700-2750 rpm). the aeromatic on a 165 hp franklin is limited to 2450 rpm cruise, hence the slower AS.
Larry Lowenkron
Member
Jeff, what/why is your Aeromatic limited to 2450 rpm, I use to have mine adjusted so that I could get 2650 on take off... I cheated and wanted the extra margin if I could get it. Of course that was before I had a digital tach, so not really sure how close to reality that was. At that time (so many years ago, I can't even remember) I didn't think about the possible inaccuracy of the mechanical tach...but that's another story. Anyway, can't you just "regulate" it by removing (or is it adding?) weights?
Larry
Larry
jeffw
New member
Larry - here's what i have been following > CAA Installation Procedure and Operating Limitations No. 11C for the F200/00-76B aeromatic on Stinson 108-2 and 108-3, and Bellanca 14-13-2/3; this is the most 'official' documentation i have found. I have also heard from folks that run their aeromatics on their cruisair franklins at higher rpms (one says that he typically runs at 2700 - 2800 rpm).
Here's some excerpts from the Operating Limitations No. 11C:
1- full throttle static should be set to 2550 rpm.
2- full throttle level flight at sea level should be 2650 rpm.
3- after those are set, the best performance and economy should be found between 2400 and 2500 rpm.
4- Noted at end of No. 11: (I paraphrase) > after extensive vibration survey by engine manufacturer on 6A4-165-B3, the aeromatic propellor was found to be in resonance between 2700 and 2800 rpm. In order to reduce exposure to this condition, a never exceed 2650 rpm is to be installed and the tach red-lined at 2650 rpm. The recommended cruising engine speed is 2400 - 2500 rpm.
i have setup documentation from kent that allows the operator to adjust the prop using the weights and shims but the other settings can only be made by a qualified prop shop. Kent tarver says that he has reset a few blades which did result in better performance; cost to ship and risk of damage in shipping.
i'm leaning towards playing it safe.
i can email you a copy of No. 11 if you would like to see it.
jeff
Here's some excerpts from the Operating Limitations No. 11C:
1- full throttle static should be set to 2550 rpm.
2- full throttle level flight at sea level should be 2650 rpm.
3- after those are set, the best performance and economy should be found between 2400 and 2500 rpm.
4- Noted at end of No. 11: (I paraphrase) > after extensive vibration survey by engine manufacturer on 6A4-165-B3, the aeromatic propellor was found to be in resonance between 2700 and 2800 rpm. In order to reduce exposure to this condition, a never exceed 2650 rpm is to be installed and the tach red-lined at 2650 rpm. The recommended cruising engine speed is 2400 - 2500 rpm.
i have setup documentation from kent that allows the operator to adjust the prop using the weights and shims but the other settings can only be made by a qualified prop shop. Kent tarver says that he has reset a few blades which did result in better performance; cost to ship and risk of damage in shipping.
i'm leaning towards playing it safe.
i can email you a copy of No. 11 if you would like to see it.
jeff
Larry Lowenkron
Member
Hi Jeff,
Yes I would like to see 11C.
Your previous message said that you were limited to 2450rpm, so can't you just adjust it to give you 2650 rpm?
I sold my Aeromatic about the time Kent bought the rights. At that time, I thought that an AD was going to be issued (my bad...as Kent says or said on his website, the prop in question probably had a strike of some sort, and the problem was not what the Feds originally said it was). I put on a McCauly 76 in. prop, and found the differences almost insignificant. Lost a few mph in cruise and gained a bit in climb. The McCauly is NOT as smooth as the Aeromatic was, nor is it as neat. I loved to land some place, people would come out to look at the plane, and I would twist the prop and watch their eyes
!! Other times, if I was feeling mean, I would ask them to grab the prop and apply some pressure, and then when it moved, I would look shocked and asked them what they did. No one ever hit me for that.
I have a 150 on my plane (red lined at 2600), so I kind of cheated to get 2650 rpm. I wanted that as a reserve. The Franklin can take that for a few minutes without batting an eye lash. I only used it for short/obstruction take offs. As I said previously, I didn't have an electronic tach, so am not sure what I really was getting. If I did it again, I most certainly would verify the tach. As it is, I now have a Horizon electronic tach (which I LOVE!) so that wouldn't be a problem. So enough of this...let us know how you resolved your issue.
Larry
Yes I would like to see 11C.
Your previous message said that you were limited to 2450rpm, so can't you just adjust it to give you 2650 rpm?
I sold my Aeromatic about the time Kent bought the rights. At that time, I thought that an AD was going to be issued (my bad...as Kent says or said on his website, the prop in question probably had a strike of some sort, and the problem was not what the Feds originally said it was). I put on a McCauly 76 in. prop, and found the differences almost insignificant. Lost a few mph in cruise and gained a bit in climb. The McCauly is NOT as smooth as the Aeromatic was, nor is it as neat. I loved to land some place, people would come out to look at the plane, and I would twist the prop and watch their eyes
!! Other times, if I was feeling mean, I would ask them to grab the prop and apply some pressure, and then when it moved, I would look shocked and asked them what they did. No one ever hit me for that. I have a 150 on my plane (red lined at 2600), so I kind of cheated to get 2650 rpm. I wanted that as a reserve. The Franklin can take that for a few minutes without batting an eye lash. I only used it for short/obstruction take offs. As I said previously, I didn't have an electronic tach, so am not sure what I really was getting. If I did it again, I most certainly would verify the tach. As it is, I now have a Horizon electronic tach (which I LOVE!) so that wouldn't be a problem. So enough of this...let us know how you resolved your issue.
Larry
Dan Cullman
New member
Jeff, If you would set up and operate the Aeromatic as per the instructions, not only will you have an airplane that climbs better but is just as fast as you are now and probably burn less fuel. You are stuck in second gear in an automatic transmission. Check your tach as described earlier. Dan
jeffw
New member
larry, my bad > i shouldn't have said that it was 'limited' to 2450; i use the RECOMMENDED 2400 - 2500. i respect the limit of 2650 as red line and that's what it turns on climb out at full throttle.
i have conferred with kent about how it is running and he has gotten me as far as i can go without sending it back to him for an in-shop adjustment, which may or may not have better results. i have gone through the initial user setup at least three times (maybe 4), so i will probably leave it where it is, in second gear for cruise; until at some time i want to risk and pay for the shipping back to kent for a shop readjustment.
i also realize that running it at 2450'ish doesn't get the max hp out of the engine, but i feel like i am playing it safer by not running the prop up to 2650 for cruise.
larry, i'll email you a scan of the 11C this weekend.
jeff
i have conferred with kent about how it is running and he has gotten me as far as i can go without sending it back to him for an in-shop adjustment, which may or may not have better results. i have gone through the initial user setup at least three times (maybe 4), so i will probably leave it where it is, in second gear for cruise; until at some time i want to risk and pay for the shipping back to kent for a shop readjustment.
i also realize that running it at 2450'ish doesn't get the max hp out of the engine, but i feel like i am playing it safer by not running the prop up to 2650 for cruise.
larry, i'll email you a scan of the 11C this weekend.
jeff