stunthanger.com
Speed,Combat,Scale,Racing => Speed Talk => Topic started by: Dennis Holler on July 03, 2024, 10:04:18 AM
-
So I ordered a set of Perky plans, don't think I'll be dropping coins on a Zalp-K though! n~ Maybe it will be the slowest Perky LL~ LL~
What are some other engines people use? I've seen some older Cox Conquest, so Nelsons... mayeb some older OS MAX and ST stuff... Does anyone run older Fox or Torpedo Greenheads?
How bout a sparkie Ohlsson .19 front intake on methanol... VD~ at least it would be period correct!
Would a fella be allowed to use a CDI or something for the ignition timer instead of the stock points? I was reading they were an issue with higher speeds above 12-13000 rpm...
-
OPS SE .15 from Bill Hughes at B&L Hobbies.
-
I would stay away from anything with an iron piston if you want to hot rod it.
MM
-
Dennis,
Remember they use only 10% nitro fuel for glow, no limit on ignition or diesel. Attached are the rules and a plan. Have fun play with props.
Best, DennisT
-
So I ordered a set of Perky plans, don't think I'll be dropping coins on a Zalp-K though! n~ Maybe it will be the slowest Perky LL~ LL~
What are some other engines people use? I've seen some older Cox Conquest, so Nelsons... mayeb some older OS MAX and ST stuff... Does anyone run older Fox or Torpedo Greenheads?
How bout a sparkie Ohlsson .19 front intake on methanol... VD~ at least it would be period correct!
Would a fella be allowed to use a CDI or something for the ignition timer instead of the stock points? I was reading they were an issue with higher speeds above 12-13000 rpm...
Keep in mind, that the event was originally a postal contest, where entrants sent in their speeds, and the winner was the model that was closest to the average speed of all contestants. It was another entry level event intended to keep costs reasonable also, but we all know how that goes!! Most clubs that hold the event still hold to the average idea in addition to 1,st, 2nd, 3rd fastest. Some guys really work toward the average and that might be more difficult than you think! I was working with a former club member who was trying for the average of what was known speeds at that time, and he was using a Fox slant head .15, and we got him into the 70MPH range I think. I don't think we ever got to top speed for that engine either but it would not have been a first place contender. Figure out how you want to approach it. Lots to learn about along the way, and like most speed events, props will be a big part of your success or lack of it.
Type at you alter,
Dan McEntee
-
If you build to the original plans here are a couple of tips. figure a way to make a stronger landing gear and get the wheels farther forward. Set the angle of attack only a couple of degrees +. This will make for smoother TO and landings that will not flip over as easily. Use one ounce tip weight. You will need about 3/4 oz of fuel and may have to modify the plane some to make room. Carl Dodge fly one with an original ignition .19. You can have fun with almost any .15. Front intake side exhaust is easiest to package. TS
-
Question: Looking at the plans and seeing pictures of a few current Perky's, It looks like the plans show it built as one piece versus the top and bottom spilt planes many seem to build utilizing a "pan". I get the pan makes it stonger ( I think). Am I right in thinking you just basically split it above the crutch? Maybe use a plywood floor under the crutch... SHould the crutch be basswood for strength? Again, on this build not looking to go 120 mph. seriously just planning on average seeking so don't necessarily need to build it for a Zalp-K! although that migth be fun in the future.. y1
-
My first one was built from the kit pretty much as shown. That's where I learned about the gear and fuel tank. Best speed was 105+ with a near 50 year old ex Goodyear Rossi Mk2. Still quite flyable.
-
The idea is to build the ship to the original shape and dimension. There is no restriction on construction methods, materials or finish. You can mount the engine in any orientations. I have a kit that I got a few years ago that I will be building later this year after I get settled in our new house in North Carolina, plan on doing the split pan/top approach.
Best, DennisT
-
There are many ways to go.
I like the top & bottom approach because it lets me have access to modify and and adjust the engine, fuel tank and control system.
One big bolt secures the two parts and the bellcrank. A second smaller bolt fixes the tail end.
This is a step-by-step of my first attempt, starting with making the templates. I used an old Nelson dating back to the "unlimited" days of FAI Combat.
I silked the body halves. Later on I went to carbon vail.
The landing gear subassembly was glued in after the bottom was sanded and painted.
-
Very nice Paul! Has anyone done one with the leadouts external to the wing. I like to do take-a-parts with wing and tail, having the bellcrank on the bottom just makes it simpler to do the assembly.
Best, DennisT
-
I do external leadouts for three reasons:
Adjustability. Once you confirm that the plane flys, you can sneak them forward for more speed.
With the thin elliptical wing it's tough to get them inside.
Direct connection to the bellcrank without making a bellcrank gap in the wing.
Why worry about 9 inches of wire when 52 feet of it is out in the breeze?
The second photo was during an engine change from side to rear exhaust. A fuel tank block is being laminated.
-
My first plane has external lead outs. Much simpler of course.
-
Paul,
Very nice and clean layout. For the button bellcrank - who sells the larger say 3" size?
Best, DennisT
-
Thanks guys, those detail shots give me some ideas I can work on. Got the plans last night so digging some wood out. Why am I not smart enough to finish what I already got started first.....
Also thinking of something like these old wooden fishing lures for a paint scheme with big glass eyes. Have to think about how to paint the wings though lol
-
Paul,
Very nice and clean layout. For the button bellcrank - who sells the larger say 3" size?
Best, DennisT
I had a bad failure with buttons. I'm back to clips.
A 3" bellcrank is too much. These planes use 1" to 1.5" bellcranks.
I bought some Russian F2A bellcranks, but you can make your own from this plan.
These are not stunters. They just need some up and level. They come down by themselves.
See? The clip is built into the stubby leadout, thus eliminating both clips and buttons.
-
Do you think this event would be more popular if the plane was easier to build?
-
The plane isn't all that hard to build.
The event may be fading because the ultimate performance has been achieved.
As in 15 Carrier, Perky started out with obsolete FAI Combat engines and progressed to all out speed engines.
-
Should have been "A" profile proto or AMA scale race type plane. Much easier to build and would fly better imho.