TF 1/5 Scale P-51 ARF Assembly (1ST MISHAP!!!)
01-20-2017, 11:34 PM
#3951
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So you cut an inch off the spring inside, I take it. The first time I read it I thought you cut an inch off the strut.
Then replaced that inch with a softer spring.
I use inflatable tires to soften the landing. Morpower sells these on eBay. They sell 3, 4 and 5 inch.
Then replaced that inch with a softer spring.
I use inflatable tires to soften the landing. Morpower sells these on eBay. They sell 3, 4 and 5 inch.
01-24-2017, 04:44 AM
#3952
Thanks guys, appreciate the info.
On the Robart gear, the Robostruts spring, I cut off about an inch and then replaced it with a softer spring. This make the strut a two stage spring system. My Mustang would sit about 1/4 inch from bottoming out when still. Taking off the struts fully extended and tucked away like normal. When landing the soft stage would let the plane settle in nicely just like full scale planes do. This gives you more room for error. It makes every landing look smoother and the better your approach the better it gets. You have to really dork an approach to bounce up again.
On the Robart gear, the Robostruts spring, I cut off about an inch and then replaced it with a softer spring. This make the strut a two stage spring system. My Mustang would sit about 1/4 inch from bottoming out when still. Taking off the struts fully extended and tucked away like normal. When landing the soft stage would let the plane settle in nicely just like full scale planes do. This gives you more room for error. It makes every landing look smoother and the better your approach the better it gets. You have to really dork an approach to bounce up again.
Thanks
Kevin
02-03-2017, 10:02 AM
#3953
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I'm wondering why the inner (3rd) gun on each wing is shorter (?) than the other two. Even tho the amo exit holes beneath the wing are lined up, the front 3rd barrel is much shorter.
I'm sure there is a logic to it, just not sure what it is...
I'm sure there is a logic to it, just not sure what it is...
02-03-2017, 10:33 AM
#3954
The gun mounts are staggered to allow for a straighter ammo belt feed. Because of the wing taper the combination of leading edge taper and gun position makes the outer gun barrel protrude more, followed by the middle gun barrrel a little further back, then the inside gun barrel is so far back it can only be seen from straight in front of it.
02-04-2017, 07:05 AM
#3955
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Thanks for the reply sjhanc. I am aware of the gun staggering, what I don't understand on the p-51 is the placement of the bullet shells disposal openings on the bottom of the wing.
Pic 1 shows clearly the staggered openings for the shell exiting the wing on a Corsair, that corresponds with the staggered guns. Pic 2 shows the p-51 openings lined up in a straight line, NOT reflecting the staggered gun (?) How does that work assuming the guns are the same configuration (as on most ww2 planes)
Pic 1 shows clearly the staggered openings for the shell exiting the wing on a Corsair, that corresponds with the staggered guns. Pic 2 shows the p-51 openings lined up in a straight line, NOT reflecting the staggered gun (?) How does that work assuming the guns are the same configuration (as on most ww2 planes)
02-04-2017, 09:03 AM
#3956
My theory is that the slot in the wing bottom is made long enough to accomodate any gun mounting position. The L/H picture is the only one I could find that APPEARS to show the ejection chutes of 2 of the guns (pinkish part under the receiver part of the guns). The shell casings ejected straight down from the chamber. It also shows the middle gun is mounted forward of the 2 outer guns, I thought it was different. I was unable to find a picture that showed the bottom of the M2 or the ejector chute. Maybe some one else has that info. Also it appears that the link ejector chute could be mounted on either side, I have seen pictures showing this.
I had a lot of experience firing M60 7.62mm guns (2,000 to 4,000 rounds per flying day, for each gunner), and helping the gunner and armorer clean our guns, but I never got to fire an M2 50 cal. machine gun. My A/C were various UH1 models equipped with hand held M 60s and one H model with a side mounted gun kit (the only one with ammo feed belts and an ejected shell casing container. My pilots loved the H model Huey because the hot casings went into the box and not up to the pilots area where they sometimes went down the neck opening of their flight suits. Forward flight sometimes got real exciting as a pilot wiggled around trying to get a blistering hot casing out of the flight suit. My gunner counted rounds fired each day, partly to assess our accuracy on targets and also because we only used a barrel for 12,000 rounds, then exchanged them for new ones. My gunner also boosted the firing rate to 800 rpm by modifying the damper in the guns (not authorized but they knew we did it but they didn't check).
I had a lot of experience firing M60 7.62mm guns (2,000 to 4,000 rounds per flying day, for each gunner), and helping the gunner and armorer clean our guns, but I never got to fire an M2 50 cal. machine gun. My A/C were various UH1 models equipped with hand held M 60s and one H model with a side mounted gun kit (the only one with ammo feed belts and an ejected shell casing container. My pilots loved the H model Huey because the hot casings went into the box and not up to the pilots area where they sometimes went down the neck opening of their flight suits. Forward flight sometimes got real exciting as a pilot wiggled around trying to get a blistering hot casing out of the flight suit. My gunner counted rounds fired each day, partly to assess our accuracy on targets and also because we only used a barrel for 12,000 rounds, then exchanged them for new ones. My gunner also boosted the firing rate to 800 rpm by modifying the damper in the guns (not authorized but they knew we did it but they didn't check).
Last edited by sjhanc; 02-04-2017 at 08:22 PM.
02-04-2017, 09:09 AM
#3957
These pictures show the 2 different gun installations I used in my last Huey. I didn't like the sidemount gun because it only had 200 rounds in its magazine, when empty I had to remove the mag. and get another. The hand held gun had 2,000 rounds in the box under the seat.
Last edited by sjhanc; 02-04-2017 at 09:25 AM.
02-04-2017, 01:55 PM
#3959
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Yup, looks like the outboard gun is fed from the "bottom", the middle one from "top" and the inboard is staggered .
Seems more complicated than the typical install, wonder what the reason was.
@sjhanc You've been flying helis in Nam?
Seems more complicated than the typical install, wonder what the reason was.
@sjhanc You've been flying helis in Nam?
02-04-2017, 08:20 PM
#3960
vasek,
while I got more than 55 hours of stick time on non-combat flights, I was not a pilot at that time. I am the GI behind the gun in the pictures, my regular seat. I started as a line crew chief responsible for 8 OH-13 Bell helicopters used for recon and artillery spotting. I never got to fly in an OH-13 as, after about 3 weeks in that job they promoted me and assigned me to a UH-1C gunship as crewchief-mechanic. That lasted for two weeks then I got a UH-1D slick in which I flew in as crewchief for combat artillery support until the TET offensive when I was assigned another former gunship C model that needed a tremendous amount of work and repairs to make it mission ready. The day that the new crew chief took over my D model, it was shot down 1/2 hour after takeoff while flying over HUE citadel. Everyone except the crewchief was wounded, some serious. At that point, the war got serious and my C model was re-assigned to the gunship companies as a float. My company gave me a brand new UH-1H and told me, my gunner and 2 pilots to go get it at Cam Ranh Bay where it had been off-loaded from a cargo ship.
That was about the first week of Feb. 1968, and I stayed with that helicopter until the following June when I rotated back to the US, having completed my full year, and 625 flight hours. I heard from a friend that my old H model had a bad landing going into an artillery battery 1 week after I left Nam and the tailboom broke off. I had less than 2 years left on my enlistment so the Army sent me to Technical Inspector school, promoted me again, and I spent the remainder in Savannah Ga., where I met my future wife. At this point I was planning to get out and the Army offered me flight school if I signed for 6 more years after completing flight school. I turned them down, got out, and went back to racing cars on circle tracks and drag racing. I got into RC at that time and have stuck with it ever since. I built engines, gear boxes, and rear end gears for myself and other racers and was hired as a Corvette mechanic in a local Chevy dealership. I currently own a really nice 98 Corvette, being retired now, I have the time to spend on my hobbies, RC, building PCs, and maintaining the Vette.
while I got more than 55 hours of stick time on non-combat flights, I was not a pilot at that time. I am the GI behind the gun in the pictures, my regular seat. I started as a line crew chief responsible for 8 OH-13 Bell helicopters used for recon and artillery spotting. I never got to fly in an OH-13 as, after about 3 weeks in that job they promoted me and assigned me to a UH-1C gunship as crewchief-mechanic. That lasted for two weeks then I got a UH-1D slick in which I flew in as crewchief for combat artillery support until the TET offensive when I was assigned another former gunship C model that needed a tremendous amount of work and repairs to make it mission ready. The day that the new crew chief took over my D model, it was shot down 1/2 hour after takeoff while flying over HUE citadel. Everyone except the crewchief was wounded, some serious. At that point, the war got serious and my C model was re-assigned to the gunship companies as a float. My company gave me a brand new UH-1H and told me, my gunner and 2 pilots to go get it at Cam Ranh Bay where it had been off-loaded from a cargo ship.
That was about the first week of Feb. 1968, and I stayed with that helicopter until the following June when I rotated back to the US, having completed my full year, and 625 flight hours. I heard from a friend that my old H model had a bad landing going into an artillery battery 1 week after I left Nam and the tailboom broke off. I had less than 2 years left on my enlistment so the Army sent me to Technical Inspector school, promoted me again, and I spent the remainder in Savannah Ga., where I met my future wife. At this point I was planning to get out and the Army offered me flight school if I signed for 6 more years after completing flight school. I turned them down, got out, and went back to racing cars on circle tracks and drag racing. I got into RC at that time and have stuck with it ever since. I built engines, gear boxes, and rear end gears for myself and other racers and was hired as a Corvette mechanic in a local Chevy dealership. I currently own a really nice 98 Corvette, being retired now, I have the time to spend on my hobbies, RC, building PCs, and maintaining the Vette.
02-04-2017, 08:21 PM
#3961
In the gun box above, the 2 outboard guns share an ammo bay with around 250 (?) rounds apiece, and the inside gun has 400 rounds. The gun installation was designed for 2 slanted guns in each wing, but when pilots complained about jamming problems NAA added the extra 2 and mounted them vertically. Evidently, the new arrangement worked well and the P-51 went down in history as the plane that enabled the bombers to attack Germany more effectively, eventually ending the war.
02-05-2017, 02:20 AM
#3962
I have used spacers to keep the springs from interfering with each other. I also use heavy marine grease to help dampen the strut.
You will have to cut springs and adjust to your planes weight. The first time I cut too much and had to adjust with spacers and longer soft springs.
The end result though was the plane sat with the gear nearly compressed parked and they will extend fully when lifted off the ground.
When you land the gear allows the tires to touch without a bounce and then the weight settles on the struts making for a very smooth landing.
02-05-2017, 06:39 AM
#3963
Yes Kevin,
I have used spacers to keep the springs from interfering with each other. I also use heavy marine grease to help dampen the strut.
You will have to cut springs and adjust to your planes weight. The first time I cut too much and had to adjust with spacers and longer soft springs.
The end result though was the plane sat with the gear nearly compressed parked and they will extend fully when lifted off the ground.
When you land the gear allows the tires to touch without a bounce and then the weight settles on the struts making for a very smooth landing.
I have used spacers to keep the springs from interfering with each other. I also use heavy marine grease to help dampen the strut.
You will have to cut springs and adjust to your planes weight. The first time I cut too much and had to adjust with spacers and longer soft springs.
The end result though was the plane sat with the gear nearly compressed parked and they will extend fully when lifted off the ground.
When you land the gear allows the tires to touch without a bounce and then the weight settles on the struts making for a very smooth landing.
02-05-2017, 07:43 AM
#3964
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sjhanc,
Kudos for serving your country if I were closer to your location I would gladly have a coffee or a beer with you and hear some stories. I always wanted to be better "mechanic", I did my own servicing of my TL1000R but not being very good at it I remember one time changing the plates and putting stiffer springs on the clutch but over-torqued the bolts so one broke off... did it right the second time around tho. Sold it last year, I just couldn't drive in "normal" speed on this thing and I want to collect my pension eventually. And I envy you for living in Savannah Ga. Been there once while working on my Urban Planning Master degree, loved the place, the "military" squares grid of the old town and still remember vividly having a beer in a pub overlooking the port, nice, and that was a long time ago (in the 80's).
What scale is your P-51 in your avatar, 1/4 ? Looks impressive
Kudos for serving your country if I were closer to your location I would gladly have a coffee or a beer with you and hear some stories. I always wanted to be better "mechanic", I did my own servicing of my TL1000R but not being very good at it I remember one time changing the plates and putting stiffer springs on the clutch but over-torqued the bolts so one broke off... did it right the second time around tho. Sold it last year, I just couldn't drive in "normal" speed on this thing and I want to collect my pension eventually. And I envy you for living in Savannah Ga. Been there once while working on my Urban Planning Master degree, loved the place, the "military" squares grid of the old town and still remember vividly having a beer in a pub overlooking the port, nice, and that was a long time ago (in the 80's).
What scale is your P-51 in your avatar, 1/4 ? Looks impressive
02-05-2017, 12:00 PM
#3965
vasek, the plane in my avatar is the second B model that I had owned, it is about 1/5 scale. I converted it from a TF GS P-51D ARC in about 3 weeks time from box to test flight. The first B model was a kit built plane with a ZDZ 80rv for power that didn't make it. I had 4.5 wonderful flights with it and a flap servo failed, causing a slow motion crash just off the right side of the runway on final approach. It knocked two 5 inch diameter trees down and not much survived. I was in a hurry to get another B model done for the flying season so I bought an ARC from the lhs, cut off the rear turtle deck and scratch built the B model turtle deck. That plane lasted 177 flights before a battery disconnect caused its destruction and the only surviving part was the B model turtle deck which I glued onto another D model ARF that now has over 300 flights, 200 of which with electric power (a lot of them with the 4 blade prop) and the rest with DA 50r power.
I recently did its annual overhaul for the new flying season and found some structural cracks in the wing and fuse so I have temporarily retired it until I have time to decide what to do with it. The pictures above were taken by barracudahockey at an Ocala, FL warbird event, the first on the take off run and the second just after touchdown. It was fun flying it with electric power but I wouldn't recommend the TF plane for this, it is too heavy for the airframe, and the re-inforcements also added weight. At 29.5 lbs. it required precision handling on TO and landing.
Last edited by sjhanc; 02-05-2017 at 04:05 PM.
02-05-2017, 12:22 PM
#3966
I recently found a video of the first test flight when it still had the ZDZ 80 for power. The model doesn't have the squadron markings on it yet ( I always get a new model into test flight, then finish the markings over the next 20-30 flights. You can get a good idea of the power of the ZDZ as it yanks the plane off the ground well before I expected it to fly, and at fast idle power, too. The prop is a Zinger 26-10, good climb, but it performs much better with a 26-12. The engine proved to be too brutal for the airframe so I bought a DA 50r and installed it on the B model after the 16th flight. The electric power system was installed after about 100 flights and I tested four blade props on it. The props available at that time were either not rated for that much power, or were too large. Ramoser (Varioprops) now makes a prop (25F) that is rated for this power in 22-25 inch diameter, I plan to try one out soon.
The vidoe is on youtube at; https://www.youtube.com/watch?v=5zksqUFUi9s
The sound track of this video is poor so I had to edit it so that it is barely audible to lower the static noise.
The vidoe is on youtube at; https://www.youtube.com/watch?v=5zksqUFUi9s
The sound track of this video is poor so I had to edit it so that it is barely audible to lower the static noise.
Last edited by sjhanc; 02-08-2017 at 11:52 PM.
03-07-2017, 01:40 PM
#3967
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Is this the DLA55 muffler that will fit inside this ARF cowl?
http://www3.towerhobbies.com/cgi-bin...6&I=LXZUK0&P=K
Or is there another one specially made for this ARF?
Thanks
http://www3.towerhobbies.com/cgi-bin...6&I=LXZUK0&P=K
Or is there another one specially made for this ARF?
Thanks
03-07-2017, 04:36 PM
#3968
vasek, that muffler will stick out both sides. You will have to cut the cowl. I modified it to fit inside by having an aluminum welding shop cut off the end away from the manifold side and weld a 1/4 inch thick plug inside. Then I canted the engine cylinder head about 25 degrees off from the plane's vertical center line to get cowl clearance on that side for the manifold. The muffler cannot touch fiberglas, the heat will ruin the cowl. An aluminum or steel brace must be fabricated to connect the free end of the muffler to the motor mounts or the firewall (either will work). The 1/4 inch plug can be drilled and tapped to bolt one end of the brace to the muffler.JTEC makes an in cowl muffler for the AEROWORKS mustang that will fit inside using the stock eng. mounting.JTEC's flash welding process will crack welds loose, I take the new mufflers to the welding shop to have all of the seams re-welded. I've never had a re-weld fail.The thread editor won't let me post pictures, but you can find them in old posts in this thread, or in the Hanger 9 60cc P51-D Mustang thread.
03-09-2017, 07:10 AM
#3969
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sjhanc, I've read this thread front to back and I remember reading about a specially made muffler for DLA 55 and
this plane which would be totally hidden inside the cowl. I believe it's made by Jtech and I have a picture but looking for the order no. or a link for it.
03-09-2017, 10:05 AM
#3970
http://www.jtecrc.com/
03-09-2017, 10:29 AM
#3971
Vasek; when you place your order with Jtec, you have to specify on the order form what engine you have, what model of aircraft you have, and you want the muffler to fit totally inside of the cowl. See link to Jtec.
http://www.jtecrc.com/
http://www.jtecrc.com/
Kevin
04-17-2017, 02:48 PM
#3972
I have two more flights on the Mustang.
After the maiden the cowl was loose and missing a screw. After the second flight loose and missing a screw. Tightened them all up. Flew again. List another screw and the holes on the cowl are elongated and on one the screw is in place but the hole in the cowl is bigger than the washer. I obviously have some major vibration going on. The prop is balanced but I did not balance the spinner. So how is the best way to balance the stock spinner. I have the dubro balancer. Do you remove some material or add something?
Kevin
After the maiden the cowl was loose and missing a screw. After the second flight loose and missing a screw. Tightened them all up. Flew again. List another screw and the holes on the cowl are elongated and on one the screw is in place but the hole in the cowl is bigger than the washer. I obviously have some major vibration going on. The prop is balanced but I did not balance the spinner. So how is the best way to balance the stock spinner. I have the dubro balancer. Do you remove some material or add something?
Kevin
04-17-2017, 04:57 PM
#3974
I have two more flights on the Mustang.
After the maiden the cowl was loose and missing a screw. After the second flight loose and missing a screw. Tightened them all up. Flew again. List another screw and the holes on the cowl are elongated and on one the screw is in place but the hole in the cowl is bigger than the washer. I obviously have some major vibration going on. The prop is balanced but I did not balance the spinner. So how is the best way to balance the stock spinner. I have the dubro balancer. Do you remove some material or add something?
Kevin
After the maiden the cowl was loose and missing a screw. After the second flight loose and missing a screw. Tightened them all up. Flew again. List another screw and the holes on the cowl are elongated and on one the screw is in place but the hole in the cowl is bigger than the washer. I obviously have some major vibration going on. The prop is balanced but I did not balance the spinner. So how is the best way to balance the stock spinner. I have the dubro balancer. Do you remove some material or add something?
Kevin
Cheers,
