Perky Speed times----pix and video link

[frank carlisle]

I had the opportunity to get video of a couple Perkys flying. They are John Bryzs and Paul Smith's birds. John's was built from a Black Hawk Models kit, it has a Typhoon .15 dual exhaust engine in it. Paul's
Perky was built from plans and had a Nelson rear exhaust 15 for power.

Both planes were screamers. A down line broke on Pauls' plane which resulted in a crash. The plane was demolished. I had already put my cam corder away so I didn't get the crash on video (dang!).

Here is a link to the vid------



pix below.............

[Dave Adamisin]

Outstanding post Frank. Too bad about Pauls. Was he able to pancake on the grass or did the Rouge circle claim another good 15??

[Paul Smith]

Fortunately, only the Down line broke and it did 2 or 3 loops before bellying in. 

There were too many people around to make an all-out effort to run for the grass. 

It was pull tested with the scale and flown on .015 lines.  When I build another one I'll do the bellcrank and leadout geometry differently.  I theorize that it was hanging out too much and putting undue load on the back leadout.

[Dave Adamisin]

Looked like you got a couple good laps. Did you get more than one timed flight? Hey, hi....

[frank carlisle]

Hey Dave---John and Paul both got in maybe 4 or 5 flights each. I wanted to keep the time on the video to less than a feature film so I edited out most of the flights and prop flipping.

Typically Paul had measuring gear to check line length and thickness. The Brodak .014 solids measured in at .013.

Also I've included a picture of Bob Laabadie and Mark Warwashana both sporting casts. Both injuries were inflicted in seperate events.


Edit----I screwed up big time.....In the picture of the two fellows with casts I told you that the fellow on the left is Bob Labadie (wrong!) the fellow on the left is Brad LaPointe. DOH!

[john e. holliday]

Measuring lines with a micrometer is a no no as I have been told.  Got to have a thickness guage to check lines with.  So with only two entries, who wins?  As winning time is the average of all the contestants.  But, the main thing is is everyone having fun.  DOC Holliday

[frank carlisle]

Who'd a known a micrometer was the wrong tool?
We're doing so many new things here Doc that it's kinda hard to keep track of. I think Paul and John were just flying the Perkys to see how fast they'd go and to afford me the opportunity to catch some video for posting. The Perks caused a big enough new kit stir during last building season that I felt someone should get some video of the darn things in the air.
As per your question about us having fun......well.....yeah we're having a ball!!

[frank carlisle]

Fortunately, only the Down line broke and it did 2 or 3 loops before bellying in. 

There were too many people around to make an all-out effort to run for the grass. 

It was pull tested with the scale and flown on .015 lines.  When I build another one I'll do the bellcrank and leadout geometry differently.  I theorize that it was hanging out too much and putting undue load on the back leadout.

Paul--why do you say you used a scale for the pull test? There was no scale.

[john e. holliday]

Hey Frank,  we all got to learn.  As I used to tell them at work, "If I don't learn something new each day, something is wrong".  Myself I am still trying to find thichness gauges to use.  DOC Holliday

[Alan Hahn]

Measuring lines with a micrometer is a no no as I have been told.  Got to have a thickness guage to check lines with.  So with only two entries, who wins?  As winning time is the average of all the contestants.  But, the main thing is is everyone having fun.  DOC Holliday

Actually that looks like a Dial Caliper to me, not a micrometer. A micrometer (if calibrated and not dropped!) is more precise than a caliper (according to my Community College Machine Course handouts). A caliper is beginning to "peter out" at the 0.001" level. I am not too sure what a thickness gauge is, but a micrometer should be a reasonable measurement, especially if you take several measurements around the wire to check for roundness.

I think the real issue is how the diameter varies along the length, and how round the wire is.