Original Posted By: Warren Shoun
I am looking for recommendations on placement of the landing gear on my Piet(other than underneath)!I am building the long fuselage, with Ford A engine. Because I will operateoff of a hard surface runway, I will be installing brakes. I would like touse wire wheels, but will probably end up with standard 6.00 x 6 tires.I have heard some say that with brakes, the gear should be moved forward 4inches to avoid nosing over. Others say that with the long fuselage, theoriginal placement is fine with brakes.Any advice?Thanks, Al Swanson________________________________________________________________________________
Pietenpol-List: Landing Gear Placement
Pietenpol-List: Landing Gear Placement
Original Posted By: steve(at)byu.edu
I have diddled with that issue on two sets of gear that I have made. I havehyd. brakes and move my gear forward on the first set about 5 inches. Ifelt this was too much and went back to about 3 inches and added 2 inches tothe height. Lots of welding and flying later and I still don't know if itmakes a lick of difference. (the change on the second set had more to dowith geometry of the shock struts than brake placement, in case you werewondering.)Important user tip. If you want more than 100 landings on your gear, makesure that you use the right wall thickness tubing. :)Steve E.-----Original Message-----Alan SwansonSent: Monday, March 29, 1999 10:15 PMSubject: Pietenpol-List: Landing Gear PlacementI am looking for recommendations on placement of the landing gear on my Piet(other than underneath)!I am building the long fuselage, with Ford A engine. Because I will operateoff of a hard surface runway, I will be installing brakes. I would like touse wire wheels, but will probably end up with standard 6.00 x 6 tires.I have heard some say that with brakes, the gear should be moved forward 4inches to avoid nosing over. Others say that with the long fuselage, theoriginal placement is fine with brakes.Any advice?Thanks, Al Swanson________________________________________________________________________________
I have diddled with that issue on two sets of gear that I have made. I havehyd. brakes and move my gear forward on the first set about 5 inches. Ifelt this was too much and went back to about 3 inches and added 2 inches tothe height. Lots of welding and flying later and I still don't know if itmakes a lick of difference. (the change on the second set had more to dowith geometry of the shock struts than brake placement, in case you werewondering.)Important user tip. If you want more than 100 landings on your gear, makesure that you use the right wall thickness tubing. :)Steve E.-----Original Message-----Alan SwansonSent: Monday, March 29, 1999 10:15 PMSubject: Pietenpol-List: Landing Gear PlacementI am looking for recommendations on placement of the landing gear on my Piet(other than underneath)!I am building the long fuselage, with Ford A engine. Because I will operateoff of a hard surface runway, I will be installing brakes. I would like touse wire wheels, but will probably end up with standard 6.00 x 6 tires.I have heard some say that with brakes, the gear should be moved forward 4inches to avoid nosing over. Others say that with the long fuselage, theoriginal placement is fine with brakes.Any advice?Thanks, Al Swanson________________________________________________________________________________
Pietenpol-List: Landing Gear Placement
Original Posted By: John_Duprey(at)vmed.org
Pieters,I too, struggled with the placement of the gear on my long fuselage, and finallydecided to use the simple weight and balance spreadsheet that I had been usingon my computer.When I began building the plane, I made up a simple spreadsheet on the computerwhich listed the estimated weight and the moments of each major component ofthe plane such as engine, wing, fuel tank, pilot, passenger etc.Then as each part was built the actual weight was put into the spreadsheet andthe revised W&B was automatically computed.When it came to the placement of the gear, I figured that I wanted to have theground contact of the wheels to be about 12 degrees forward of the CG. Turnedout to be perfect. I can use the brakes pretty hard without any tendency tonose over, (the brakes are not that effective)yet it is light enough on the tailwheel,(12 lbs) to handle easily on the ground. Generally speaking, the further forward the gear is, the more squirrely the planeis on take off and landings, but too far aft and it becomes too sensitive tonosing over under braking effort.Hope this helps,John, NX114D________________________________________________________________________________
Pieters,I too, struggled with the placement of the gear on my long fuselage, and finallydecided to use the simple weight and balance spreadsheet that I had been usingon my computer.When I began building the plane, I made up a simple spreadsheet on the computerwhich listed the estimated weight and the moments of each major component ofthe plane such as engine, wing, fuel tank, pilot, passenger etc.Then as each part was built the actual weight was put into the spreadsheet andthe revised W&B was automatically computed.When it came to the placement of the gear, I figured that I wanted to have theground contact of the wheels to be about 12 degrees forward of the CG. Turnedout to be perfect. I can use the brakes pretty hard without any tendency tonose over, (the brakes are not that effective)yet it is light enough on the tailwheel,(12 lbs) to handle easily on the ground. Generally speaking, the further forward the gear is, the more squirrely the planeis on take off and landings, but too far aft and it becomes too sensitive tonosing over under braking effort.Hope this helps,John, NX114D________________________________________________________________________________
Re: Pietenpol-List: Landing Gear Placement
Original Posted By: Les Schubert
RE: Pietenpol-List: Landing Gear Placement
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Del,as my recent post on this subject says, if you build the long "corvair"fuselage, NO GEAR was ever shown on the drawings. So how do yo know whereit should be? The point of my presentation is that if you don't know whereit is to be per the drawings then this is one man's (my) best guess. Also,I use Sky Gypsy as a prime example of a much beloved Piet that was built oneway and then promptly modified to be manageable by a very able pilot. May Isuggest that the 500 less the Sky Gypsy are the 499 piets that never fly?Chris-----Original Message-----
Del,as my recent post on this subject says, if you build the long "corvair"fuselage, NO GEAR was ever shown on the drawings. So how do yo know whereit should be? The point of my presentation is that if you don't know whereit is to be per the drawings then this is one man's (my) best guess. Also,I use Sky Gypsy as a prime example of a much beloved Piet that was built oneway and then promptly modified to be manageable by a very able pilot. May Isuggest that the 500 less the Sky Gypsy are the 499 piets that never fly?Chris-----Original Message-----
Re: Pietenpol-List: Landing Gear Placement
Original Posted By: "del magsam"
----- Original Message -----
----- Original Message -----
Re: Pietenpol-List: Landing Gear Placement
Original Posted By: del magsam
Re: Pietenpol-List: Landing Gear Placement
Original Posted By: "walter evans"
Subject: Re: Pietenpol-List: Landing Gear PlacementHey Folks,In the papers I received with my plans there is a memo of sorts that talks to the movement forward of the landing gear on the stretched fuselage version. If there is any interest I could probably get it scanned and post it.Dave HallFayetteville, NC________________________________________________________________________________
Subject: Re: Pietenpol-List: Landing Gear PlacementHey Folks,In the papers I received with my plans there is a memo of sorts that talks to the movement forward of the landing gear on the stretched fuselage version. If there is any interest I could probably get it scanned and post it.Dave HallFayetteville, NC________________________________________________________________________________
Re: Pietenpol-List: Landing Gear Placement
Original Posted By: "del magsam"
Just jumping in with my two cents.In spite of what engine you use or equiptment you put on, the CG is still inthe same window. Assuming that the gear is hooked to the same attachpoints,if you use the split gear, the only way to relocate the wheels is bychanging the style of the "V". If you do this, as the gear moves thru it'srange of motion while the bungees are flexing, the toe-in/toe-outcaster/camber is all going to be different from original.Except for moving engine forward about 2" (A-65 long fuselage) tocompensate for my fat arse, the CG is still in the window(way to the rear).I built the split gear to the plans, and it seems to handle fine riding onthe mains waiting to leave the earth.walt----- Original Message -----
Just jumping in with my two cents.In spite of what engine you use or equiptment you put on, the CG is still inthe same window. Assuming that the gear is hooked to the same attachpoints,if you use the split gear, the only way to relocate the wheels is bychanging the style of the "V". If you do this, as the gear moves thru it'srange of motion while the bungees are flexing, the toe-in/toe-outcaster/camber is all going to be different from original.Except for moving engine forward about 2" (A-65 long fuselage) tocompensate for my fat arse, the CG is still in the window(way to the rear).I built the split gear to the plans, and it seems to handle fine riding onthe mains waiting to leave the earth.walt----- Original Message -----
RE: Pietenpol-List: Landing Gear Placement
Original Posted By: owner-pietenpol-list-server(at)matronics.com
Del,The mounting points are the same. The mounting hardware is the same. The Vjust changes shape as the axle is moved back. Looking at the wood gearshown 1932 F & G Manual, the forward leg of the V is more vertical andshorter than the aft leg of the V which is longer. As the axle moves backthe legs begin to equal out in length. This is needed on the long "corvair"fuselage as used on sky gypsy because you moved the CG aft and you increasedvertical surface area aft.There are three conditions:1) low speed aircraft handling on ground with negligible total aerodynamiceffects.2) high speed aircraft handling on the ground with considerable totalaerodynamic effects.3) aircraft in flight. Landing gear has limited aerodynamic effects.In case one, you are dealing with taxiing, speeding up for take off andslowing down after landing. This is with little or no help from the rudderdue to slow speeds. The farther forward the gear is located on thefuselage, the greater the distance between the CG and the gear axle. Also,lowering the tail slides the gear even further forward. We are used to theCG being defined as the point of rotation of all reactions but this onlyapplies in flight. If a wheel is touching the ground, then the wheelcontact point, which is just below the axle becomes the point of rotationbecause that is where the airplane is "attached" to the ground. The greaterthe distance between the CG and this ground "attachment" point, the harderit is for the pilot to transition from ground mode to flight mode. Smallchanges forward in axle placement greatly increase the tendency to groundloop.In addition, as the axle is moved forward, there is an increased sidesurface area aft of the "attach" point of the aircraft with the ground.With a forward axle, any crosswinds would cause the tail to swing rightaround into the wind. Don't forget that any surface moved from in front tobehind the axle hurts you twice becuase forward of the axle it was helpingto counter what was behind the axle. Now it is adding to what is behind theaxle. Also, the distance from the axle to the end of the ship increases theleverage that side surface area exerts in a crosswind. Granted, this mayincrease rudder effectivity but we are dealing with a flying surface that istrying to use air on the downwind side of the fuselage to move the fuselageback toward the windward side. The downswind side of the fuselage isessentially blanked out so the rudder has limited effectiveness.In case two, a too far forward placement of the axle will cause increasedground looping tendencies due to CG placement relative the axle and sidesurface area relative the axle as noted in the previous paragraph. Withthe axle too far forward, it will be virtually impossible to lift the tailfor takeoff until an abnormally high speed in ground roll is attained. Atail wheel airplane is not designed for this. It will present a high dragprofile to the relative wind and the takeoff rolls will be too long. Itwill also increase the structural loading on the tail with some pretty largeimpact loads. You will be ripping the tail skid/wheel off on a regularbasis.In case three, the too far forward placement of the gear would put verticalsurface area (the wheel sides) far forward of the CG. This will tend tocancel the stabilizing effect of the vertical stabilizer. As cool ascovered spoked wheels look, this is a big reason why many that have usedspoked wheels with fabric covering have removed the fabric covering. Thetwo big vertical discs negated the stabilizing effects of the verticalstabilizer.In summary, the axle needs to placed as far aft as possible but withconsideration of limiting the tendency to noseover. Others posted messagesto this list indicating the degree angle that the axle needs to be forwardof the CG. This is do true but it truly neds to be understood. A picturewould really help to see what is meant. We tend to think of the CG as apoint on the wing where the ship balances. This is a valid CG location butthis is the longitudinal CG or the CG along the longitudinal axis. We needto also consider the other axes. There is a CG about the vertical axis anda CG about the lateral axis. Combine these three and you get a single pointabout which all the mass of the aircraft is located. A guess on thePietenpol, with its high wing, is that it is located at or about the centerof the instrument panel. If you level the ship and then hang a plumb bobfrom this point and then make the angle forward of this (someone elsementioned it in an email a minute ago, was it 7 degrees?), your axle shouldoptimally lie on that line. This would be the axle location that is as farback as possible yet far enought forward to keep you from nosing over.I hope this helps.Chris Bobka-----Original Message-----
Del,The mounting points are the same. The mounting hardware is the same. The Vjust changes shape as the axle is moved back. Looking at the wood gearshown 1932 F & G Manual, the forward leg of the V is more vertical andshorter than the aft leg of the V which is longer. As the axle moves backthe legs begin to equal out in length. This is needed on the long "corvair"fuselage as used on sky gypsy because you moved the CG aft and you increasedvertical surface area aft.There are three conditions:1) low speed aircraft handling on ground with negligible total aerodynamiceffects.2) high speed aircraft handling on the ground with considerable totalaerodynamic effects.3) aircraft in flight. Landing gear has limited aerodynamic effects.In case one, you are dealing with taxiing, speeding up for take off andslowing down after landing. This is with little or no help from the rudderdue to slow speeds. The farther forward the gear is located on thefuselage, the greater the distance between the CG and the gear axle. Also,lowering the tail slides the gear even further forward. We are used to theCG being defined as the point of rotation of all reactions but this onlyapplies in flight. If a wheel is touching the ground, then the wheelcontact point, which is just below the axle becomes the point of rotationbecause that is where the airplane is "attached" to the ground. The greaterthe distance between the CG and this ground "attachment" point, the harderit is for the pilot to transition from ground mode to flight mode. Smallchanges forward in axle placement greatly increase the tendency to groundloop.In addition, as the axle is moved forward, there is an increased sidesurface area aft of the "attach" point of the aircraft with the ground.With a forward axle, any crosswinds would cause the tail to swing rightaround into the wind. Don't forget that any surface moved from in front tobehind the axle hurts you twice becuase forward of the axle it was helpingto counter what was behind the axle. Now it is adding to what is behind theaxle. Also, the distance from the axle to the end of the ship increases theleverage that side surface area exerts in a crosswind. Granted, this mayincrease rudder effectivity but we are dealing with a flying surface that istrying to use air on the downwind side of the fuselage to move the fuselageback toward the windward side. The downswind side of the fuselage isessentially blanked out so the rudder has limited effectiveness.In case two, a too far forward placement of the axle will cause increasedground looping tendencies due to CG placement relative the axle and sidesurface area relative the axle as noted in the previous paragraph. Withthe axle too far forward, it will be virtually impossible to lift the tailfor takeoff until an abnormally high speed in ground roll is attained. Atail wheel airplane is not designed for this. It will present a high dragprofile to the relative wind and the takeoff rolls will be too long. Itwill also increase the structural loading on the tail with some pretty largeimpact loads. You will be ripping the tail skid/wheel off on a regularbasis.In case three, the too far forward placement of the gear would put verticalsurface area (the wheel sides) far forward of the CG. This will tend tocancel the stabilizing effect of the vertical stabilizer. As cool ascovered spoked wheels look, this is a big reason why many that have usedspoked wheels with fabric covering have removed the fabric covering. Thetwo big vertical discs negated the stabilizing effects of the verticalstabilizer.In summary, the axle needs to placed as far aft as possible but withconsideration of limiting the tendency to noseover. Others posted messagesto this list indicating the degree angle that the axle needs to be forwardof the CG. This is do true but it truly neds to be understood. A picturewould really help to see what is meant. We tend to think of the CG as apoint on the wing where the ship balances. This is a valid CG location butthis is the longitudinal CG or the CG along the longitudinal axis. We needto also consider the other axes. There is a CG about the vertical axis anda CG about the lateral axis. Combine these three and you get a single pointabout which all the mass of the aircraft is located. A guess on thePietenpol, with its high wing, is that it is located at or about the centerof the instrument panel. If you level the ship and then hang a plumb bobfrom this point and then make the angle forward of this (someone elsementioned it in an email a minute ago, was it 7 degrees?), your axle shouldoptimally lie on that line. This would be the axle location that is as farback as possible yet far enought forward to keep you from nosing over.I hope this helps.Chris Bobka-----Original Message-----
Re: Pietenpol-List: Landing Gear Placement
Original Posted By: "Christian Bobka"
----- Original Message -----
----- Original Message -----
> RE: Pietenpol-List: Landing Gear Placement
Original Posted By: Kip & Beth Gardner
Re: Pietenpol-List: Landing Gear Placement
Original Posted By: ZigoDan(at)aol.com
Subject: Re: Pietenpol-List: Landing Gear PlacementIn a message dated 2/3/03 7:18:52 AM Eastern Standard Time, dilatush(at)amigo.net writes:> When it came to the placement of the gear, I figured that I wanted to have > the ground contact of the wheels to be about 12 degrees forward of the CG. > Turned out to be perfect. I can use the brakes pretty hard without any > tendency to nose over, (the brakes are not that effective)yet it is light > enough on the tailwheel, (12 lbs) to handle easily on the ground.I am curious John, how did you arrive at the 12 degrees forward of the CG ? Or is that 12 inches ?-dennis________________________________________________________________________________
Subject: Re: Pietenpol-List: Landing Gear PlacementIn a message dated 2/3/03 7:18:52 AM Eastern Standard Time, dilatush(at)amigo.net writes:> When it came to the placement of the gear, I figured that I wanted to have > the ground contact of the wheels to be about 12 degrees forward of the CG. > Turned out to be perfect. I can use the brakes pretty hard without any > tendency to nose over, (the brakes are not that effective)yet it is light > enough on the tailwheel, (12 lbs) to handle easily on the ground.I am curious John, how did you arrive at the 12 degrees forward of the CG ? Or is that 12 inches ?-dennis________________________________________________________________________________
Re: Pietenpol-List: Landing Gear Placement
Original Posted By: "Christian Bobka"
Subject: Re: Pietenpol-List: Landing Gear PlacementI owned a 1938 Aeronca chief at one time. The gear was far forward, to me it made a forgiving aircraft, and I think one would have had to worked hard to put it on the nose. The down side is it was hard to see out of when in the three point attitude. You had to land with your peripheral vision when three pointing. And it took a long time to get the nose up. But with the gear as far forward it put a lot of weight on the tail, and made it feal more positive to me. In retrospect my father-in-law has a Champ, and one day I was by myself in the front seat, during the run up with brakes set I relaxed the stick forward and almost put it on the nose, scared the crap out of me. With my Chief and his Champ side by side you could really tell how far forward the gear was on the Chief compared to his Champ.And it seems to me when I used to build model RC planes putting the gear farther forward help ground stability. Now I have not followed this discussion that well but felt like telling you guys this just in case it might help. If not nothing is lost.DNADan________________________________________________________________________________
Subject: Re: Pietenpol-List: Landing Gear PlacementI owned a 1938 Aeronca chief at one time. The gear was far forward, to me it made a forgiving aircraft, and I think one would have had to worked hard to put it on the nose. The down side is it was hard to see out of when in the three point attitude. You had to land with your peripheral vision when three pointing. And it took a long time to get the nose up. But with the gear as far forward it put a lot of weight on the tail, and made it feal more positive to me. In retrospect my father-in-law has a Champ, and one day I was by myself in the front seat, during the run up with brakes set I relaxed the stick forward and almost put it on the nose, scared the crap out of me. With my Chief and his Champ side by side you could really tell how far forward the gear was on the Chief compared to his Champ.And it seems to me when I used to build model RC planes putting the gear farther forward help ground stability. Now I have not followed this discussion that well but felt like telling you guys this just in case it might help. If not nothing is lost.DNADan________________________________________________________________________________
Re: Pietenpol-List: Landing Gear Placement
Original Posted By:
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----- Original Message -----
Re: Pietenpol-List: Landing Gear Placement
Original Posted By: "Jon Botsford"
Subject: Re: Pietenpol-List: Landing Gear PlacementDave, I would be very interested in seeing this if you are able to scan and post.Don Hicks________________________________________________________________________________
Subject: Re: Pietenpol-List: Landing Gear PlacementDave, I would be very interested in seeing this if you are able to scan and post.Don Hicks________________________________________________________________________________