Dowmer

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Thanks Katniss, good recommendations. Do you have any trouble with them kicking off before they reach the desired pressure? I noticed some comments earlier about people having this issue with other brands.

J

vertical grimmace

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[QUOTE=HoundDog;11719021]Maybe look at getting an Ultra precision brand valve? They have a great reputation, with good needles. Then you can toss the Robart valve. Dreamworks list the UP valve for around $35.

Katniss

No. The one I use has an on/off switch on the unit. I let it get to 100-110 and then unhook the fill chuck while the unit is still running and then switch it off.

70 ragtop

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Here is a video using the ESM 190 A retracts with no restrictors, then using wheel collars as restrictors in the up line, then on both lines. I like the brass restrictors you can get from BVM. Tamjet, DreamWorks, Robart ect all sell these. This is just one way to do it

BTW, I said down line when I tightened first collar, that is the up line
Enjoy

http://www.youtube.com/watch?v=IkuwrtSaOAU

Dowmer

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Here's a couple pics from my RCSB build thread. working cowl flaps, cockpit kit and other stuff. Still bashing though. Deadstick has a bit of a jump on me. I do show in detail how to make a glass mold and hood of the D9 if anyone cares. It was a learning experience for me but it turned out well.

Dowmer

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Ragtop,
Thanks man, great vid. I'm pretty new to the pneumatic gear so it is a great tutorial.

Jason

70 ragtop

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Nice work Jason!

I was checking out your 190A thread a few months back...that came out really nice!
Keep it up

Chris Nicastro

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Nice cowl flap mech.
Just a suggestion from my experience doing the same on the TF GS Corsair cowl; the fiberglass segments will probably relax and flatten out as they age and heat cycle. Since the cowl is polyester resin not epoxy it will change shape with heat and especially the small flap parts.
Im going to redo mine and use carbon matting and CA glue it to the back surface of an uncut cowl. CA glue is very aggressive on this kind of polyester resin. Afterwards Ill cut the parts off the cowl and redo the hinges and cable mounts.

I found that after a few flights the Dubro hinges started coming off the flap or the bulkhead ring. Some small screws will really help in addition to the glue. These parts experience pretty high stresses and temps due to internal cowl pressure and engine temps.

Anyway, I hope you take another look at it.

Dowmer

My Feedback: (1)

Ragtop, thanks for the props.

Chris, thanks for the advice. The cowl flaps are actually the epoxy resin from the cowl I cut off. However, I can tell that they have flattened a little already and I can definitely believe that the Dubro hinges could come off later. I tried to add extra epoxy over the hinges to "beef up" the area but I shall see how it holds up. I might have to do something like you suggest later on if they don't hold.

Jason

70 ragtop

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Anytime, hope it helps!
Think of the wheel collars doing the same thing as the brass restrictors. I had a hard time getting these gear to smooth out using the needle valves..... as in I couldn't smooth out the bounce. The difference is the needle valves only regulate the exhaust flow, not the incoming flow. Restrictors limit flow in both directions. A restrictor in both lines will restrict flow on both sides of cylinder, in both directions....if that makes any sense.

The U.P. valves VG mentioned are great, very good quality valve. They are loosing favor with the new solenoid valves that are coming out, but the UP valves are time tested and proven. I haven't really had a problem with the Robart red valve, they can just be VERY sensitive. Have to remember its just closing off the exhaust air from the cylinder. Close it all the way, gear won't move, get threadlocker in there, they won't work right.

edit: Forgot to mention that you don't have to do this on most gear. Basic retract valve with built in needle valves on the exhaust side usually work fine. Call this the next step if they don't

Mike

vertical grimmace

My Feedback: (1)

Yah, it seems many default to the Robart products, when there are a bunch of other options. The selenoid valves are very attractive, and I have one in my spring gear in my Pica 190. What is great is that they plug right into the RX with no servo or linkage needed. I have had more problems with servos and linkage issues on my valves than anything else. So this is welcome to me. Not sure if they have a dual valve that allows you to control flow, but that would really be sweet.
That is good to know about the cowl flap flattening out. I will have to look at that when I do my cowl for the TA 152, as I will have cowl flaps on it as well. Actually operated by a thermostat! Of course the thermostat will be worthless with the electric set ups! lol
I am going to do mine different though as far as linkage go. I will attach a short section of golden rod tube out on the outer edge of the flaps. Then I will thread the golden rod cable through all of the tubes on the individual flaps. I will have 2 servos on each end of the cable. The expanding, and contracting action of the cable will open and close the flaps. It works great and is very simple. I saw this in a thread a guy did on a P 47. There is video as well.

Dowmer

My Feedback: (1)

VG,
I was originally going to do that method with the outer band but I couldn't with my D9 for a couple reasons. First, I don't have a continuous circle of flaps. The engine sticks out the bottom and the top obviously doesn't have them either. Then on the starboard side the flap in front of the supercharger inlet is fixed as well and doesn't move so I only had various different flaps in different positions moving which was a real PITA. That was why I used the Evo method with the flex cable and linkage so I could chose what I wanted to move.

I think the flap layout and look is a little different on the 152 so you will probably be able to do the concentric circle method with the two servos mounted at the top on each side of the non-movable top plate with the louvers. BTW, rule of thumb for placement of the ring cable I read is about 50-60 percent of the length of the cowl flap. Of course, if the flaps are open in between like the D9 then you will have to have them a little further outboard at about 80 percent so they are hidden by the interlocking tabs. Experimentation is the key...

Like Chris pointed out. Probably the best way to make the flaps is to cut them off the cowl itself so you have the right shape, but you could make a template with the correct diameter and use G-10 and sandwich pieces together to have them kept their curve without flattening.

J

deadstick79

I'll second that... Thankks Ragtop!
Dan

vertical grimmace

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Could you not have a tube installed on the fixed flaps as well? Even though the cable is attached and passing through them, they will not move if attached to the front of the airframe. I have a great cowl for my TA 152. I think that the concern is once the flaps are cut off of the cowl, they will flatten out. I have some thin fiberglass sheet, that I might laminate on to the inside face, before I cut them off. I think my cowl is polyester resin. One thing for sure, it will take some experimenting.

Oh, I received 4 1/5th scale MG 151/20 cannons yesterday. They were 3d printed. Looks like they will fit very well. This is the wing root cannon for the FW 190 D and TA 152. If anyone is interested, I will provide pics.

Dowmer

My Feedback: (1)

VG,
on the circle method if you have the cable running through some of the non moving flaps you won't get the right action required to get the same amount of movement from the others because the fixed flap acts like a movement restrictor. I think you will be OK on the 152 and I think the flap in front of the supercharger on the 152 moves.

Your idea of epoxying some FG on the flaps before you cut them off is right on. I wish I did that, but it is too late for me. They are holding up ok though. Show mw some pics of those guns man! They sound great. Insert jealous look here.

Jason

HoundDog

My Feedback: (49)

Of course vertical grimmace everyone is interested Pictures are worth a 1000 words ... and maybe 1000 Questions.
So Pics PLZ.

vertical grimmace

My Feedback: (1)

Well, here you go. I got 4 of these. They come in pieces and you just glue it together. I used a piece of 1/8" carbon rod to splice the barrel together. The barrel is fairly fragile, so I think the dowel is mandatory. Not sure where else I would have found one of these. Saved me a bunch of time scratch building it.

That is a 15" ruler.

deadstick79

Hey All,
Totally bummed! Ruined a fine Turnigy prop using a Hobby King propeller drill jig!!!!!!!!!
Holes were so far off that making them bigger to GET THERE would compromise safety to say the least!
The holes are supposed to be 30mm across the hub diagonally on center.
Could some one let me know if any of the DLE engines have the same cross dimension? Cause HobbyZone sells several jigs for the DLEs' but don't give the dimensions in their listings for each one they sell!..
Many Thanks,
Dan

vertical grimmace

My Feedback: (1)

This is an electric motor right? You need to track down the specs on the bolt pattern. Most of the 500 cc sized gas engines, copied the DA 50. So, DA and DLE at least are the same for the 50cc sized engines.

Again, I would install a single bolt prop adapter, then you do not need to bother with boring your props. Also, you can still use this one that got bored wrong. If your motor is the same pattern as the DA,DLE, Then go to Valley view and get the single bolt prop adapter from them. It will be very easy to install on a motor.

kahloq

Deadstick....use the prop washer that came with your motor(the round plate that gets bolted down on top of the prop with the bolts). Center it on the prop using the center hole and clamp down. Use a pencil and mark the 4 holes and then use a drill press to drill the holes. If you don't have a drill press, you can use a hand drill...but you've got to be careful to keep the drill vertical as best as possible. If you off a little here or there, you can hollow out the holes a tad to get the bolts to fit through and fit into the motors tapped holes. Once the prop is sandwich between the prop washer and the motor, its not going anywhere. Ive had to hog out those holes a few times to get things lined up and these were on gas motors with lots of vibration, No issues at all with a prop being compromised.

Take a photo of the prop you alresady drilled and with the prop washer over it so I can see how far off it is and whether there would be anything to worry about making the holes bigger. Another option is, turn the prop 45 degrees and drill 4 new holes.with the prop washer used as spacing. You can fill the old holes with wood glue.

vertical grimmace

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Look at how easy this is though, and it will eliminate any future grief. If you are committed to drilling your props though, you will play hell without a drill press. If you plan on saving and re-drilling your bad prop, I would fill those old holes with a glued in dowel. Glue does not do much, if anything for structural strength. Any wood worker knows this. It was creative advice to rotate it and re-bore the thing. I am just trying to make your life easier in the future. These things are like $30. Well worth it.

thunder21

My Feedback: (2)

Well that sucks. The drill jig I use for 50cc motors is 30mm center to center of diagonal 5mm holes. You can compare the prop washer included with the motor against the drill jig to ensure proper size. The instructions on the TBM page have worked well for me using a hand drill to drill maybe a dozen props success.

These guides ensure straight through drilling of props and spinner backplates. TBM offers several versions. Many include a screw and washer to hold the prop or spinner backplate in place for accurate drilling. Simply put the prop or spinner backplate on the 10mm stub, then tighten using the screw and washer. Use of a drill press is best, though a hand drill can be used. We recommend drilling the backplate and prop at the same time if they are new. Stack the backplate, prop and drill jig together so that the drill jig is on the spinner backplate. It is best to drill from the backplate into the propeller because this will minimize the issues on the front side of the backplate as the drill bit exits the backplate. Be sure to use a sharp drill bit as this will also minimize the issues when the drill bit exits the part. Only drill through the backplate and about three quarters of the way through the prop. Then remove the drill jig, and rest the prop on a piece of hardwood and drill the rest of the way through the prop. Check the first hole’s exit. If the hole is not clean on the exit, you may prefer to put the drill jig on the front side of the prop. Use the one hole to line up the drill jig properly by installing a screw, then drill the remaining holes. This will make a cleaner hole.

https://www.troybuiltmodels.com/cate...ll-Guides.html

kahloq

Seems like good advise.

deadstick79

Thanks Troops!
Done and done! I sanded the varnish off the center of the prop and used the prop ring and the engine shaft to mark the holes and drilled them out on my son's cheap $60 dollar drill press early yesterday morning! Enlarged the holes using my trusty screw gun and it worked great! I can save the other prop too by rotating as suggested! By the way, I bought that cheapy drill press from my son for a box of 44mags
Are you guys balancing your spinners?
Kahloq.... do we even have to balance the SK Hobby spinners? Or do they come balanced?
Thanks again,
Dan
Ps... she's basically ready now! Balances beautifully with a tad nose-heavy! Just have to organize the million wires switches and air lines for ease of assembly and balance my props! I will try to get my son to video the maiden! I have all the plastic eye-candy glued on and the strut covers as well! Was going to leave them off til maidien but figured that with their angle compared to the strut, it should create some nice slow-down drag on landing!

Ramstein44

My Feedback: (157)

Pictures..