rajul

My Feedback: (58)

Excellent! What grit size did you use?

w8ye

My Feedback: (16)

I don't think it matters on the drywall screen

frets24

My Feedback: (15)

Being a plumber I always have mesh sand tape on hand, it's 180 grit, and have used it for "grip washer" on numerous occasions and it' been great. Same as drywall sanding screen only it comes on a roll and is 2 1/4" wide. If you have a sanding bar then you probably have some adhesive back sandpaper for it as well, so you could put a couple pieces of that together if you don't feel like dropping $6.00 on sanding mesh.

on the FA100.... if you are in a dive at 7/8 throttle or more you are probably over reving the engine with any prop combo. the result is floating the valves and likely leaning the mixture due to inability to draw enough fuel to meet the RPM. Either way probably not good. I've always been told that a dive with more than 1/2 throttle is a bad idea for both engine and airframe. the explanations and logic that followed (mostly self explanitory and not expanded on here) sounded good to me so I've pretty much avoided high power dives or excessively steep powered descents.

Any other thoughts on high power dives out there? Have these suggestions just been folklore or do they carry weight?

bonesonpoint

Well, I've got a feeling you may be right. I've never flown a fast plane with a four stroke on it before. Always 2 strokes. The Saito 91 that I've been flying for 10 years is on the same Cub today that I put it on 10 years ago so it has never had the chance to rev too fast. I never really thought of a four stroke as a fast plane engine but I just had to have that Saito sound for this plane.

I hope someone else has some theories but my hunch is that you are right and even if you're not, I think 7/8 is fast enough. That's exactly what it sounds like in the air, like the thing finally just turns so fast it can't draw enough fuel to feed it. I don't think I'm really losing much speed by pulling back on the stick a little bit and unless someone else has an answer, that's what I'm gonna do. While I'm doing that I'll tinker with it and hope someone else comes up with a better theory but I suspect you have nailed it. It doesn't feel right anyway going full throttle in a dive with a 4 stroke. I'm not sure they are made for that.

BTW, what I have been calling a dive is actually what you are calling a steep powered descent. I also had never heard that rule of thumb that you mentioned about the dives and steep descents. It all makes sense to me. I'm still in the two stroke frame of mind and had never run into the problem before. I think I need to cut my 4 stroke some slack.

Thanks for the info.

rajul

My Feedback: (58)

Well, I managed to make a couple of grip washers with 180 wet & dry, using medium ca as bonding agent. Looks pretty good. Time to test them

Slats!

My Feedback: (1)

Hi I have a saito 100 with the inverted pitts muffler. Looking at the two is the only difference a valve for the smoke. Can you convert them. Thanks

Rudolph Hart

Have you tried some bigbore fuel lines and fittings yet? i think sullivan make them.

Rudolph Hart

Welcome back rajul and good luck with the drive washer.Could you gently centre punch the drive washer,no balance problems.

My 82a is in drydock because i can't get a cline or iron bay reg to sort out the high tank position here in aus.Is there another way around that problem even if it's temporary.I'd like to fly it but the plugs being drowned at low rpm and an onboard glo which i have for another plane will just mask the problem.

While the 82 is out of service i might pull it out and put it back on the test bench so i can put the needles back where they were.Is anyone interested in seeing how slow you can idle one?..it used to go down to 1000rpm briefly and 13/14 hundred reliably.Have others done the same and if you have please post here with your experiences when you did that.Lot's of fun when you get a good solid transition too.Let me know and i'll post some pix or for the doughting souls out there i'll do a vid when my son gets back.Cheers brothers

tz250w

I acquired my 82a a couple weeks ago and flew it for the first time last weekend in heavy gusts and snow and again today in prime conditions. All I can say is WOW!

I have it mounted in a World Models Cap 232 .46 and it will hover the little plane a slightly less than half throttle. Idles slow forever and turns the 14X6 strong for unlimited vertical. Sounds nice too!

Only problem is it does seem to spray a bit back out of the carb. Should I grab a stack for it?

Rudolph Hart

Yes they spray gobs out of the carb.Tried a stack,12 bucks here in aus and could'nt prime the engine the way i normally do no matter what i tried.I bore a hole in the cowl and block the carbie with my little finger.Two strokes of the prop and you can hear it's wet.A quick and gentle back flip and she's away.That cap 232 sounds interesting,can you post some pics please?

Hobbsy

My Feedback: (102)

OF, I don't want to rain on your parade but they only spray gobs out of the carb when they're set too rich or are over propped.

Rudolph Hart

Sorry all i should have explained i was referring to an inverted mounting and the right size prop 14x6.It's why i need a regulater to cope with the high tank position relative to the carb and assumed that tz250 had also mounted his 82 tha same way in the cap.Any idle figures dave?

bonesonpoint

No, I hadn't thought of that and that might just fix the problem. It makes sense. Like I said earlier, this is the first fast plane I've ever run a 4 cycle on. I'm used to pegging a 2 cycle out and going for top speed. I was talking to some of the guys in the club this morning and they agree with the idea that it's probably not a good idea to go WOT with a 4 cycle in a fast plane and a steep descent. The hobby shop owner told me had seen some bad results. I think as long as it never does the coughing/sucking air thing to me in level or reasonably steep descents I am good with it. On steep ones, and especially on a dive, I think I am going to start backing off until I start leveling out. That's what I've had to do to avoid the problem and now I think it is the best plan anyway for the engine and the plane. I'm glad I posted here because I was uninformed on how to use a 4 cycle on a fast plane.

I will remember that big bore fuel line and fitting tip though, if the problem pops up in level or slightly steep flight. Thanks!

Hobbsy

My Feedback: (102)

O, how about an inverted .80? APC 14x6, 15% WildCat

PS, did you put the O-ring between the velocity stack and the carb.?

NM2K

My Feedback: (14)

Yep, like Hobbsy says, you can't choke it without the o-ring between the carb and the velocity stack. Big opening there allowing air into the carb.

Power management (like backing off the throttle in a dive) is one of the signs of an advanced pilot. Fortunately, with all of the 3D flying going on today, many more folks are aware of power management than in the recent past.


Ed Cregger

tz250w

It's not completely inverted, looking at the front the head is at about 8 oclock. Needle is good, slow might be a tad rich but it shouldn't be off by much as it idles nice and slow (forever) and doesn't load up at all with very good response to full throttle.

w8ye

My Feedback: (16)

I still see an old timer come to the field on occasion and he flies wide open throttle the whole flight. Few people do that anymore.

rcdude7

My Feedback: (264)

Most of us these days (myself included) overpower our planes so much that extended full throttle running would evetually rip the wings off.

w8ye

My Feedback: (16)

Very true

Rudolph Hart

If thats a wide blade apc 14x6 @ 9600 i'm impressed dave.

First time i fitted the stack i did'nt notice the gap.Bought an o ring set and found the right size but still can't prime that way(finger over stack)removed the 0 ring and you can see a mark where it touches all the way round,can't figure it right now.

Is there any way apart from major surgury on the tank position and assuming i can't get a cline or ironbay fuel reg to fix the problem? i'd like to fly it SOON as it's the only model i have thats in one peice(turned one into balsa dust last weekend)apart from the one i'm building now and i've a three week wait till the 220 arrives.Anyone with a temporary fix or something they have tried that worked or nearly worked??

Rudolph Hart

Hi and well good on him i say.You gotta go full throttle against the fun police i reckon.If the aeroplane manufacturer says power it with a 180 saito i say why not stuff a 220 in there and go vertical..it's a lot of fun for the aged

Cherokee Flyer

Finger over the muffler outlet, a few flips at wide open throttle, throttle to idle, apply glow starter and flip backwards and it will start right up. Have never chocked a Saito engine nor needed to.

L.

NM2K

My Feedback: (14)

If the old timer at the field built his model in the old days, he would pretty much have to fly it full throttle, or it would fall out of the air.

Ever fly a Falcon 56 with the recommended .15 to .19 sized engine? 8>)


Ed Cregger

w8ye

My Feedback: (16)

Around here in 1970 everyone and his brother had a Falcon 56 with a OS S30 R/C engine with the airbleed carb and no muffler.

NM2K

My Feedback: (14)

I built one or two using the slightly larger OS .35S version engine. It still wasn't smartly powered with that.

If you went larger, say with a K&B .40, you then didn't have enough room in the fuselage for the requisite 8 oz. fuel tank.

Goldberg remedied that with the introduction of the Falcon 56 Mk. II, but they should have lengthened the fuselage by a couple of inches behind the wing's trailing edge. There were lots of seriously nose heavy MkII's with K&B .40 engines being flown for a while there. It was still a great flying plane.


Ed Cregger