Thunderbolt flies (photo's)

LAST EDITED ON Nov-22-04 AT 10:13 PM (CST)
 
Went out to Buder Park today. Put in the test flights. Found out I need to open the cowling up some to let more air thru. The turning capabilities are outstanding. I can see why Billy designed this airplane. Turns like a combat plane. Flat and it grooves as well. I don't think I could ask for a better combination.

EDIT: Randy said it would fly like a 39oz ARES and it does.

Bottom photo's are how I opend up the cowl to allow for crankcase cooling.

EDIT: I have been looking over the post pics and found it took 3 months total. 1 month to build and 2 months to finish. This includes 1 week to build mold bucks and two weeks off for school. What I am trying to get across is if you have determination you can do things very rapidly. So if your new new at this hobby keep your eyes on the ball.

Robert, your new Jug is great. In the couple of months or so I've been on this forum your Thunderbolt posts have been ,by far,
the most inspirational. Thanks for making the effort, taking the pictures, and putting them on here.

LAST EDITED ON Nov-21-04 AT 07:23 PM (CST)
 
> Robert, your new Jug is great. In the couple of months
>or so I've been on this forum your Thunderbolt posts have
>been ,by far,
>the most inspirational. Thanks for making the effort,
>taking the pictures, and putting them on here.
>
>
>
> Bill Ervin

Thank You I am glad someone got something out of it. If you need any help just drop me a line.

>
>Thank You I am glad someone got something out of it. If you
>need any help just drop me a line.

Awww, c'mon Sparky!
A LOT of people got a LOT out of your posts on this project!
Not everyone can see a world class design being created. When is the new video coming out?
Planning on being at the NATS next summer, too, with my son. I won't have a Jug this year, but if I can get it together, you might be interested in what I do bring.
We'll have to get together.
Bill <><

LAST EDITED ON Nov-21-04 AT 11:18 PM (CST)
 
>When the character of a man is not clear to you, look at his
>friends.
>Japanese Proverb

Bill I could not resist. Here are some of my friends.

Hi Spark,
The fellow on the far right looks almost like my twin!
Bill <><

Before you shaved your goatee??

Hey Robert
Where did you find my prison PAMPA team photo??I thought it was lost? Hey McMillin where are you????Thanks David

LAST EDITED ON Nov-23-04 AT 10:02 AM (CST)
 
Looks like my group of friends, nice to be friends with allota guys bigger then yourself.

Randy Ryan <>< aka MOON
AMA 8500
SAM 36
BO all my own M's

LAST EDITED ON Nov-23-04 AT 10:29 AM (CST)
 
Say, I didn't know that Clean from the Kansas City Area routinely flew with the guys at Buder Park in St. Louis. That sure looks like him on the far right. Pictures don't lie.

Robert,

For just a second, I could have swore this was a picture of Nils Norling and his flying buddies. Better known around Oregon as Brother Speed. Are you sure your not Nils secret Twin Brother?

Hmmm. A typical fast combat group at Buder on any give Saturday morning.

Huzzah, huzzah, huzzah. Feels good doesn't it at the end of the line? Congratulations.

Something else that will make you happier.........It will get even better with trim!
Sounds like it will come along great
Bill <><

>Went out to Buder Park today. Put in the test flights. Found
>out I need to open the cowling up some to let more air thru.
>The turning capabilities are outstanding.

Robert,
I have been opening the air outlet towards the front of the pipe on the Copperhead. This has eliminated all cooling problems. These mostly had to do with the pipe getting hot and transfering the heat to the engine. (I didn't have enough tunnel clearance with the bigger diameter pipe, additionally. Probably not your problem, but the inlet/outlet balance and side of tunnel clearance are good things to double check.)
I also unloaded the engine (PA61) by using a 12x3.75 2-bladed prop for now instead of a 12 inch three blade, as the engine seems just a tad tight still and this was an additional cooling help. I will start to use slightly smaller three blades as I determine the engine is getting broken in. It seems to need a lot of time to get settled down.
Your model looks great, good luck in trimming it out. Hope all goes well.

hey you say your going to fly at the 05 nats i might go just to see ya fly this thing thanks for all your post i learn a lot.

>I also unloaded the engine (PA61) by using a 12x3.75
>2-bladed prop for now instead of a 12 inch three blade, as
>the engine seems just a tad tight still and this was an
>additional cooling help.

Which 12" three blade?

Brad,
I tried a Bolly 12x4.5 which ended up too fast. The Eather undercamber 12x3.5 was too large in diameter and loaded the engine to the point of a bog in some maneuvers. Same with the Eather 12x3.75 flat back. The Eather 12x3.75 2 blade makes the engine very happy right now.
Chris...

LAST EDITED ON Nov-22-04 AT 05:47 AM (CST)
 
Incidentally, opening up the front of the cooling duct doesn't necessarity mean better cooling. See:

http://www.supercoolprops.com/ARTICLES/ducted_cooling.htm

(Of course, for a Stunt plane, more drag isn't necessarily bad.. unlike in pylon racing..)

Buder park? I've flown there once or twice, won my first ever Fast Combat contest there (using a OS .25 FSR!). How's Gary Frost these days?

LAST EDITED ON Nov-23-04 AT 11:53 PM (CST)
 
>Incidentally, opening up the front of the cooling duct
>doesn't necessarity mean better cooling. See:

I didn't open the front hole up any more. just the inside routing passage. I made it more free flowing. The tunnel now is a stright through shot.Also used styrophome food container along with aluminum tape as a insulator for fuel tank.

I saw Gary Frost two weeks ago. He's doing fine and was looking for a pilot for his racer.

What is the matter with Gary Frost, did he mess up his foot again?

>Brad,
>I tried a Bolly 12x4.5 which ended up too fast. The Eather
>undercamber 12x3.5 was too large in diameter and loaded the
>engine to the point of a bog in some maneuvers. Same with
>the Eather 12x3.75 flat back. The Eather 12x3.75 2 blade
>makes the engine very happy right now.
>Chris...

Hey Chris, what pipe are you using and what pipe length? Also, do you have a rubber ducky on it? First off, if that 12 x 4.5 is too fast, you can repitch, you know. It is nice to be able to take something out of the package and use it, but repitching is OK, too.

Alternately, you could lengthen the pipe a bit and simply slow the engine down. Matt was using a 13.5 x 4.25 three-blade on his PA 61. Nice 4-cycle with 5.2 to 5.3 second lap times. Just a slight break at the top of the loop. He was using a 65 size pipe, however, and no rubber ducky (robs power).

>
>Hey Chris, what pipe are you using and what pipe length?

Aero 65 pipe. 17.25.

>Also, do you have a rubber ducky on it?

No.

First off, if that
>12 x 4.5 is too fast, you can repitch, you know.

Yes.

It is nice
>to be able to take something out of the package and use it,
>but repitching is OK, too.

Yes, it is. I can spend all night on a Bolly and still not have it run as smooth as an Eather prop out of the box!

>
>Alternately, you could lengthen the pipe a bit and simply
>slow the engine down. Matt was using a 13.5 x 4.25
>three-blade on his PA 61. Nice 4-cycle with 5.2 to 5.3
>second lap times. Just a slight break at the top of the
>loop. He was using a 65 size pipe, however, and no rubber
>ducky (robs power).

I'm trying to replicate a local guys set-up. So far my engine bogs in the eights with his numbers.
If you could tell me what Matt's prop, fuel, venturi, plug and pipe length are, I would be interested.

Thanks,
Chris...

>Brad,
>I tried a Bolly 12x4.5 which ended up too fast. The Eather
>undercamber 12x3.5 was too large in diameter and loaded the
>engine to the point of a bog in some maneuvers. Same with
>the Eather 12x3.75 flat back.

Huh... that prop is very low load. Richard is always saying I should be running more load. The "red" is definately more load in the manuever. I use the "green" 3.75 most of the time.

>Brad,
>I tried a Bolly 12x4.5 which ended up too fast. The Eather
>undercamber 12x3.5 was too large in diameter and loaded the
>engine to the point of a bog in some maneuvers. Same with
>the Eather 12x3.75 flat back. The Eather 12x3.75 2 blade
>makes the engine very happy right now.

I agree - it sounds way too tight. There should be no issue with a 12-3 3/4 3-blade U/C, if that's what you want to run. I much perfer the performance with the same prop cut to 11.5, but mine will happily turn the 12".

I don't know what the rest of the setup might be, but even with a Werwage pipe 17.25 sounds too short, given that the likely launch RPM is going to be around 9800-10000 rpm. With an Eather pipe, it'd expect it to be definitely too short.

Brett,

Do you think I should go out on the pipe a ways?
I'm installing an exit lip now.
I'm going to start cutting a 1/8" at a time off the three blade to see if it likes it, and find out if it would be fine with a little larger diameter than your suggested 11.5. Maybe the darn thing still isn't broken in?
Internal airflow isn't right I'm sure, but I'm baffling a couple things as I go. I'll tell you how it works out.

LAST EDITED ON Nov-23-04 AT 10:21 PM (CST)
 
Chris,

Your PA is bogging down?? Please explain. Is it breaking and then bogging? Or is it never breaking and just bogging down from where it is running at the time. I am curious about this. It should have plenty of poop to turn those props you are talking about.

I run eather 4 blade 12 X 3.5 or a 3.6 or a 3.75 depends on the wind. Yeah they are very low in pitch but there is 4 blades. Its a decent load but not anything real heavy.

How is it setup?

How much time on bench and how much in the air?
Venturi?
Shims(head clearance)?
Plug?
Fuel?

What RPM do you launch?

I run my 65 at 17 1/4-3/8 and I usually end up at about 10500 or higher if it just stinky hot out! (11,100 when the front bearing goes out...) Seems to make the most usable power without any bursts or bogs when the bearing starts to eat itself. It is really weird. They run the bst right before they crap.

How old is it? How long have you run it.

PS Sparky your plane kicks a-s-s!

Yes please run a closed tunnel from entry to exit. That makes for a happy pipe!

>PS Sparky your plane kicks a-s-s!
>
>Yes please run a closed tunnel from entry to exit. That
>makes for a happy pipe!

Thanks Doug. I have closed up the hole in the cowl.

LAST EDITED ON Nov-24-04 AT 05:40 AM (CST)
 
Some speculation. I'm wondering if temperature and/or altitude might make a difference in the way the prop runs on Chris's plane as opposed to Brett's experience.

Very nice Sparky!!

Just beautiful, Sparky. Well done.

The cooling problem could be related to the size of the air outlet. Got any pictures of that? As I expect you know, you need more air outlet than inlet otherwise the hot air expands and stagnates inside, effectively reducing or eliminating the flow of cooling air.

LAST EDITED ON Nov-23-04 AT 09:49 AM (CST)
 
>Just beautiful, Sparky. Well done.
>
>The cooling problem could be related to the size of the air
>outlet. Got any pictures of that? As I expect you know,
>you need more air outlet than inlet otherwise the hot air
>expands and stagnates inside, effectively reducing or
>eliminating the flow of cooling air.
>
>Ted

Thank you Ted. The out let is just like a sewer pipe 2 to 1. My outlet is plenty big enough I think don't you?

[photo not recovered: 419aa1500d364886.jpg]

LAST EDITED ON Nov-23-04 AT 11:26 AM (CST)
 
Robert,

It's not the size of the pipe exit in the bottom block that matters in this layout (just my opinion). It's the size of the hole at the front of the pipe outlet. From the tunnel floor up (or down if it's on the gear) to the bottom block minus what the pipe displaces. Is that clear? The vertical opening through which the pipe passes right before it gets to the pipe exit opening. The air has to squeeze past that area and could be causing you problems.

Edit: Also, you may be losing some air at the exit just behind the cowl. A lot of cooling air may be dumping there allowing the pipe to heat up without a method of circulating the air out. Just some things to think about if your having problems. Frank Williams did an article about this in SN a few years ago. His testing seemed to indicate that closing the whole system (no outlets) with a 1 to 2 (inlet to exit) ratio resulted int he best cooling. I'd probably try enlarging the area around the pipe (if possible) right before it gets to the pipe exit area and taping over the air exit just aft of the cowl then try it.

LAST EDITED ON Nov-23-04 AT 11:42 AM (CST)
 
Just to go along with what Randy Powell is saying (I think). The decided on procedure according to Randy Smith, and other top level fliers, is to do away with the initial practice of having an opening where the header/pipe junction is. This opening was always shown on the plans in the past and used on planes before. As was explained to me, it doesn't allow enough air to pass over the pipe. Now just a front inlet and the pipe outlet is all that is being used. This really works better in all the applications I have seen.
First thing Randy Smith told us when we first had Aaron's Geo(bolt) XL out was to close up that hole. We did.
Bill <><

>Just to go along with what Randy Powell is saying (I think).
> The decided on procedure according to Randy Smith, and
>other top level fliers, is to do away with the initial
>practice of having an opening where the header/pipe junction
>is. This opening was always shown on the plans in the past
>and used on planes before. As was explained to me, it
>doesn't allow enough air to pass over the pipe. Now just a
>front inlet and the pipe outlet is all that is being used.
>This really works better in all the applications I have
>seen.

Yep - I fried a pipe or two, and had some bad runs, from that. I ended up taping up all the outlet holes in the cowl and it was immediately much better. I also ended up putting an "extractor" lip right at the front of the aft outlet to even out the flow around from the top and bottom of the pipe.

>>Just to go along with what Randy Powell is saying (I think).
>> The decided on procedure according to Randy Smith, and
>>other top level fliers, is to do away with the initial
>>practice of having an opening where the header/pipe junction
>>is. This opening was always shown on the plans in the past
>>and used on planes before. As was explained to me, it
>>doesn't allow enough air to pass over the pipe. Now just a
>>front inlet and the pipe outlet is all that is being used.
>>This really works better in all the applications I have
>>seen.
>
> Yep - I fried a pipe or two, and had some bad runs, from
>that. I ended up taping up all the outlet holes in the cowl
>and it was immediately much better. I also ended up putting
>an "extractor" lip right at the front of the aft outlet to
>even out the flow around from the top and bottom of the
>pipe.
>
> Brett

Yup, me, too. It was really painful because on the purple pond scum (the Final Edition's pseudonym per my good "friend" Bob Hunt) I had these like really sexy, swoopy air outlets in the cowling right by the header. Very cool looking. Trouble was I absolutely cooked the pipe even though the entire pipe tunnel was open from the end of the cowling (about four inches aft of the engine exhaust) to well behind the end of the pipe. The small diameter of the pipe next to the header literally collapsed under the tie wraps because it got so hot the epoxy gave up.

I solved the "aesthetics" problem by putting carbon veil over the exit holes on the inside of the cowl and spread a couple coats of thin CA over it to seal the pores. I then cut the side out of a 7-Up can, painted it to match the purple pond scum color and taped it over the first four or five inches of the pipe tunnel beyond the engine cowl.

Problem disappeared.

>Robert,
>
>It's not the size of the pipe exit in the bottom block that
>matters in this layout (just my opinion). It's the size of
>the hole at the front of the pipe outlet. From the tunnel
>floor up (or down if it's on the gear) to the bottom block
>minus what the pipe displaces. Is that clear? The vertical
>opening through which the pipe passes right before it gets
>to the pipe exit opening. The air has to squeeze past that
>area and could be causing you problems.
>
>Edit: Also, you may be losing some air at the exit just
>behind the cowl. A lot of cooling air may be dumping there
>allowing the pipe to heat up without a method of circulating
>the air out. Just some things to think about if your having
>problems. Frank Williams did an article about this in SN a
>few years ago. His testing seemed to indicate that closing
>the whole system (no outlets) with a 1 to 2 (inlet to exit)
>ratio resulted int he best cooling. I'd probably try
>enlarging the area around the pipe (if possible) right
>before it gets to the pipe exit area and taping over the air
>exit just aft of the cowl then try it.

I have closed the small opening and there are no obstructions in the pipe tunnel. All should be fine now.

Robert,

Can't wait to hear how it works.

Very Very nice and inspiring.
Takes me about 3-4 mo. to get the wood out of the box.
You do you have to kill to get plans for this jewel?

Sorry Charlie, so far there ain't no "plans". Just "bucks and lost foam jigs". Bill just had some working drawings.
Bill <><