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General Forum => Model Aerodynamics => Topic started by: piecost on January 22, 2018, 06:19:37 PM



Title: Bernie Hunt spreadsheet
Post by: piecost on January 22, 2018, 06:19:37 PM
Fellow forum members,

Can anyone post supporting documentation for Bernie Hunt's static Stability spreadsheet?

Cheers


Title: Re: Bernie Hunt spreadsheet
Post by: Olbill on January 22, 2018, 10:22:18 PM
Don Slusarczyk can.


Title: Re: Bernie Hunt spreadsheet
Post by: Hepcat on February 06, 2018, 07:37:37 AM
Piecost,
Reg Boor did most of the clever stuff on Bernie's Indoor Design spreadsheet but how much he will have records or memory of after all these years I don't know. Reg was an aerodynamicist with Avros all his workinglife.  He is regularly seen Indoor Flying, almost always nowadays with Scale Models.  So far as I remember the tricky parts in the calculations were things like downash estimates which is where Reg did a lot of work.
John


Title: Re: Bernie Hunt spreadsheet
Post by: piecost on February 06, 2018, 05:13:30 PM
Thanks for the reply John. I have met Reg once, when he flew at the Brabazon Hanger in Filton,  but I wasn't aware of the spreadsheet then. I was hoping to find a published paper along the same lines as your propeller design review, which enabled me to reverse engineer your spreadsheet. I will have to brush-up on my vortex theory to unpick this one.

Cheers

Tim


Title: Re: Bernie Hunt spreadsheet
Post by: Soc on February 06, 2018, 09:49:18 PM
Hi Piecost

I too would like to see any supporting documentation for the BH spread sheet.

I got a copy a few years back and reverse analyzed it to work out the algorithm.

Most of the steps follow conventional aerodynamic theory and mathematical modeling methods,
but there are a few oddities along the way, which might be mistakes or fudges or something else.

There have been a number of articles on modeling low RE drag in the NFFS symposiums over the years
and I think ideas from some of these are used in the spread sheet,
but so far I've not been able to relocate the bits I think I read.
Its possible that the relevant material was in an article that I read in an on-line collection somewhere.

I'd be very happy to discuss the matter with you and send you my notes.
PM me if you would like to take this further.

Sean


Title: Re: Bernie Hunt spreadsheet
Post by: frash on February 07, 2018, 08:07:56 AM
Has anyone asked Bernie? The last that I heard was that he retired from indoor competition but was flying RC sailplanes outdoors.

Fred Rash


Title: Re: Bernie Hunt spreadsheet
Post by: Soc on February 11, 2018, 06:42:31 PM
Piecost

I sent you a PM with a contact address.
If you contact me via that address I can send the notes I've managed to dig up.

There are a few reasonably coherent pages that seem to cover everything.

Sean