In building my ZP38 I am at a point in the center section to install the flaps. I am not doing fowlers. How many have used the internal linkage method shown on Ziroli's plans and do they work well. I've seen a couple of pics of others planes and they have the servos hanging out the bottom of the wing. Is there a problem installing them internally or did they just go the easy route?

I put servos' in for all four flaps. Just my preference I guess as I am not a big fan of bell cranks on a high load surface. You can hide the servo in the wing if you don't like the looks of the servo hanging out of the wing.

Carey

A servo on each flap was my plan, the way I interput the plans is with the servo and linkage inside the wing. I have a PCK laser kit and it comes with ply flap horns. I am considering replacing them with aluminum ones that I will make using the ply ones as a pattern, or do you think the ply is ok. I have had ply horns break on me before

the internal linkage as shown on the plans work fine as long as the horns are made from aircraft grade ply the holes will not develope excess play, if you make them from metal then you have to worry about metal to metal contact causing possible rf noise.

I will be using ball link type connectors such as Rocket City through out the whole plane, in 4/40 of course. That should help to eliminate the RF interferance. The PCK horns are aircraft ply, I just have a trust issue w/ply horns. Been there, crashed that.

I am about the same place you are in construction. Have decided to do ball link connectors as well just like I always do. Have been undecided about the Fowler flaps and was wondering why you decided not to go that way. I am leaning against also just because of the added construction time and I'm certainly not headed to the scale masters anyway.

Looks like I'm not doing them for the same reasons as you. Don't want to complicate the building process any more than it already is nor am I going to Scalemasters either

I built my ZP-38 per the plans with 4/40 pushrods and Sullivan clevices of all 4 flaps. One servo per flap. 4 years and over 100 flights and never had a problem. If I had to set it up again I would use a JR Matchbox. What a pain it was seting up 4 servos to all work the same. PS use a high tourqe servo if you want them to come down under a load. Mike

flying2bill:
Take a look at the bell cranks sold by Nelson Hobby. They are made of T6 aircraft aluminum and use the Rocket City 4-40 ball link. They have two ball bearings that the mounting bolt swivels aroung. They are very strong and slope free. They come as a kit that you put together.

K_sonn, those are some cool looking bell cranks, I'll keep them in mind, however I am doing plug in wings so will need seperate servos in the wing panels, Might could use them in my mock p38 trainer though.
Luckyb001, enlighten me on JR Match box please. I have hi-torq servos for the whole project. Most are 100 oz, a few 80 oz. Also planning to run 6 volt packs for the servos.

JR has a electronic device called a Matchbox. It will allow you to use up to 4 servos together and set the travel and endpoints for all 4 to be the same. A Friend of mine just used one to set up a plane and he said it worked great. You can also reverse servos if you need to. I have not used one yet but it would be great on a P-38. Mike

this matchbox gizmo sounds just like the contraption I need for the flaps, tips on who is selling them?

The matchbox is a neat device, but doesn't it require it's on power supply?

Vince

Matchbox can be purchased direct from Horizon or any dealer that handles JR equipment. The unit has the option of using it's own battery but that is not required. If you do not connect a separate battery pack, it simply uses the receiver power supply like any direct connected servo.

Does it munch much power, I spent most of today dinking around with the flaps in the center section of my P38. used a servo reversing y-harness and lots of adjusting trying to get them to move the same, can envision the nightmare when I add the outboard flaps to the mix, Matchbox is sounding better every minute I work on these things

I can't say with absolute certainty how much additional power the match box would use but I would expect it to be minimal. I would think the draw with 4 servos attached would be slightly more than 4 direct connected servos. When driving as many servos as you will be, the Matchbox would be insignificant. I am using Multiplex servos in mine which are individually set via a programmer which accomplishes the same function in a different manner. Keep in mind that the Matchbox only works with JR digital servos.

Blows that plan, I already have a dozen 100oz servos bought for this project. back to adjusting the linkages

I kind of thought it sounded that way which is why I mentioned it. Wouldn't be so bad if we were still buying $20 servos but those days are gone.

F2B......Don't get discouraged....its not as hard as you think......most important thing to keep in mind is assymetry....meaning that make sure the inboard flaps and outboard flaps are rigged to extend the same degrees(or distance) if there is a slight disparity between the I/B flap and O/B flap on the same side it will be ok as long as each "Paired "flap is the same.....the best way to get even flap deployment is to mount the servos identical and use identical geometry...IE same servo horns and same flap horns mounted in the same distance from the L/E of the flap....take an extra few minutes to make calculations before you do the installing and you will come out with minimal adjusting to do....the idea here is to avoid uneven flap deployment creating an unwanted roll when flaps are extended....finished my "Z" B-25 just last week and the flaps came out pretty darn close without too much work....B-25 has same similar I/B and O/B flap arrangement as the P-38......Good Luck....Bill.....

The JR Matchbox only works with JR Digital servos? I couldn't find anything about this on their website. I was planning on using one of these, darn!!!

later

I was working with my inboard flaps setting them up and I noticed that one servo moves faster than the other and also seems to have more travel. both are identical servos and both are brand new. Using a servo revesing y harness I can adjust the end point on the reversed servo. Will the difference in speed of deployment be a problem or do I need to go through all my servos and pair them up by speed?

Check out Futaba item MSA-10 might be what you need. You still have to make all flaps identical for them to be in unison, ie horn location from all aspects. Regards G

F2B....What kind of servos are you using?........ck voltage at each servo to ensure thats not a problem......I have seen some of the cheaper servos that are the same but move @ different speeds.....Bill....

My apologies guys as I passed on some bad information about the Matchbox from JR. I always try to verify info before I repeat it but I dropped the ball on this one. The Matchbox works with ALL JR SERVOS, BOTH ANALOG AND DIGITAL. I got bad info from some pretty reliable flyers but we were all wrong. I had one in my goody pile waiting for another project so I went to the shop and just spent an hour checking it out. My advice on setting them up is to get things fairly close by using the radio travel adjustment and linkage setups as the changes with the Matchbox are not infinite but certainly sufficient for final adjustments. As an aside for future projects, I'm using Multiplex servos for my P-38 flaps as they are infinitely adjustable plus you can adjust the speed. The slowest speed will be a perfect flap speed so all I have to do is flip the switch and forget it. I prefer JR servos but I'm eperimenting with these and although not as strong as JR's, they have great holding power and have workd fine in a 35% 540

Well that makes the day seem a little brighter. I finished running all the stringers for the center pod but I'm going to wait until I have the wiring and plumbing done to finish the sheeting, will move on to the next phase of construction whilest I aquire one of these here matchbox do-hickies