Voyeurger
Well-Known Member
I apologize for the "book", but the background is real important.
I have started the final stage of a build that came to me 80% (or so) done. The build involves a two seat Falconar Teal amphibian (puller?) begun in 1969. I have discovered correspondence between "my" builder (Bob), and another builder who had recently completed and flown his Teal (Larry). The letters begin in 1969 and run through 1974. The plane, built EXACTLY to plan specs and addenda by Larry, was a dog and Larry believes he discovered most of the plan flaws. These were passed on to Bob in time to save him the same grief. The correspondence was extensive and detailed and Bob built (or not) according to Larry's suggested mods.
I am attaching a sketch that Larry attached to one of the letters.
View attachment 9599
The first Teal kit finished was flown by its builder Martin Jones in the summer of 1973. This occasion was covered by the magazine Sport Aviation.Larry sent Martin a letter of congratulation with a list of questions. Mr. Jones replies state that, "I made two flights and barely staggered around the airport both times". He goes on to say,"I think the junction formed by the cowling, windshield, and wing is causing some bad airflow and killing some lift on inboard wing area". He has much more to say before, "I have given up on the airplane". This correspondence resulted in Larry writing to Bob in August of '73, "I believe we (Martin Jones and Larry) are both experiencing some loss of propeller efficiency .... because of engine mounting. I..say this engine should be mounted up higher and clear from the top of the airplane to allow air movement through and between the two".
About a year later, Sept. of '74, Larry writes Bob (who is only half built at this time), "I believe that now I have the answer as to why Martin Jones... did not have as good results with 150HP as I did with 125. (Larry's engine mount gave 5 degrees upthrust while Martin's was horizontal). And why the Kingfisher has poorer results with 150HP as the same with 125. The location of this engine and propeller configuration causes the C.G. to change with power on. The more power, the farther forward the C.G. goes....out of the C.G. range. I flew a Lake amphibian (pusher) while at Portland ...and this plane flies altogether different". He goes on to say the pusher configuration the C.G. does not change when the prop is BEHIND the C.G. range. "So really, by raising the engine more, or by increasing H.P. (in the puller) you will increase this force and move the C.G. farther forward, thus increasing the problem".
The Teal was a failure overall. Only five kits made it to the registry. Bob made many changes (wing area increased, droop tips, lightened considerably). I am still able to make more changes for the better, and I think Robert Nelson would have if he hadn't passed away.
I am very grateful for any thoughts or input as to engine mounting configuration. I'm sorry this went on so long.
Gary
I have started the final stage of a build that came to me 80% (or so) done. The build involves a two seat Falconar Teal amphibian (puller?) begun in 1969. I have discovered correspondence between "my" builder (Bob), and another builder who had recently completed and flown his Teal (Larry). The letters begin in 1969 and run through 1974. The plane, built EXACTLY to plan specs and addenda by Larry, was a dog and Larry believes he discovered most of the plan flaws. These were passed on to Bob in time to save him the same grief. The correspondence was extensive and detailed and Bob built (or not) according to Larry's suggested mods.
I am attaching a sketch that Larry attached to one of the letters.
View attachment 9599
The first Teal kit finished was flown by its builder Martin Jones in the summer of 1973. This occasion was covered by the magazine Sport Aviation.Larry sent Martin a letter of congratulation with a list of questions. Mr. Jones replies state that, "I made two flights and barely staggered around the airport both times". He goes on to say,"I think the junction formed by the cowling, windshield, and wing is causing some bad airflow and killing some lift on inboard wing area". He has much more to say before, "I have given up on the airplane". This correspondence resulted in Larry writing to Bob in August of '73, "I believe we (Martin Jones and Larry) are both experiencing some loss of propeller efficiency .... because of engine mounting. I..say this engine should be mounted up higher and clear from the top of the airplane to allow air movement through and between the two".
About a year later, Sept. of '74, Larry writes Bob (who is only half built at this time), "I believe that now I have the answer as to why Martin Jones... did not have as good results with 150HP as I did with 125. (Larry's engine mount gave 5 degrees upthrust while Martin's was horizontal). And why the Kingfisher has poorer results with 150HP as the same with 125. The location of this engine and propeller configuration causes the C.G. to change with power on. The more power, the farther forward the C.G. goes....out of the C.G. range. I flew a Lake amphibian (pusher) while at Portland ...and this plane flies altogether different". He goes on to say the pusher configuration the C.G. does not change when the prop is BEHIND the C.G. range. "So really, by raising the engine more, or by increasing H.P. (in the puller) you will increase this force and move the C.G. farther forward, thus increasing the problem".
The Teal was a failure overall. Only five kits made it to the registry. Bob made many changes (wing area increased, droop tips, lightened considerably). I am still able to make more changes for the better, and I think Robert Nelson would have if he hadn't passed away.
I am very grateful for any thoughts or input as to engine mounting configuration. I'm sorry this went on so long.
Gary
