Hollein Introduction F5J Build Update

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DoverSail
Posts: 50
Joined: Thu May 07, 2020 4:18 pm

Hollein Introduction F5J Build Update

Unread post by DoverSail » Mon Dec 21, 2020 11:52 am

Hello everyone!
For the last few months, I have been working on my first balsa build; a 2.9M Hollein "Introduction F5J" e-sailplane. It is a laser-cut it, with four servos (two for flaps, elevator, rudder). I have been documenting the build process on RCGroups, but I figured the local crew might find some of this to be interesting as well!

The "Introduction" is meant to be a low-cost foray into the very competitive F5J glider class, wherein primarily carbon-fibre moulded high-performance sailplanes with powerful geared motors compete to fulfil the task of staying airbourne for ~10 minutes and then landing on a spot. The carbon F5J planes are some of the most beautiful engineering out there for model planes; they have expertly designed wings, many with six servos to allow for very precise control of the aerofoil. Competitors are effectively rewarded for using their motor to climb to a low altitude as points are deducted for launching to higher altitudes.

In general, these ships cost thousands of dollars and most competitors have multiple planes with different masses to handle different flying conditions. While there are none of these competitions out our way, the envelop-pushing designs of this class benefit all modellers eventually. The Introduction F5J is basically a really affordable wooden version of these planes, with a simplified wing. There is a 6-servo wing version available as well, called the "Inside F5J".

Anyway, I have been building this for a while now, with lots of advice from local building expert John O and from Whacker as well.

I hope you enjoy the photos showing my progress so far. I have finished the fuselage, tailfeathers, and wing centre panel; now I am working on the outer panels (the wing breaks down into three pieces) and then comes covering! This will be covered in translucent white in the centre and outer panels, transparent violet in the mid panels, and with black wingtips for visibility.

I hope you will get to see this big model tearing up the skies at a solid 5kph this spring at a Shannon Park near you.
FullView.jpg
Attachments
The Wing Centre Panel
The Wing Centre Panel
The profiled and sanded balsa nose block, containing the Hacker A20 22L-EVO outrunner, which will directly drive the 11x6 folding carbon prop.
The profiled and sanded balsa nose block, containing the Hacker A20 22L-EVO outrunner, which will directly drive the 11x6 folding carbon prop.
A closeup of the rudder and h-stab
A closeup of the rudder and h-stab
Front view of the sanded fuselage. I will either paint or cover this in white with black pinstripe.
Front view of the sanded fuselage. I will either paint or cover this in white with black pinstripe.

DoverSail
Posts: 50
Joined: Thu May 07, 2020 4:18 pm

Re: Hollein Introduction F5J Build Update

Unread post by DoverSail » Thu Jan 21, 2021 10:46 am

Well, some progress has been happening on my Introduction behind the scenes!

The fuselage is nearly done, having been painted and sanded six times now.
All the wing joiners are in place and seemingly lined up well. When it is all together, the left wingtip and right wingtip height above the table has an error of 5mm, which I believe is acceptable on a 3M wing.

I have been working on covering the wing. There is a flat centre panel, which bolts to the fuselage. Then on each side is a removable wingtip. The wingtip is made up of two sections, a mid-section and a tip-section, and a winglet or "ohren" at the very tip.

I will be covering the centre section in translucent white, and the tip sections in transparent violet, and white on the tip panel.

I tried a thousand times to attach my photos but they all come up as "invalid file type" now, so I don't know what the problem is. They're only ~2.5MB each so they should fit...

Anyway, I uploaded the photos to an imgur album and hope that you enjoy. The photos show my covering progress on the wingtip section.

If anyone can help me understand why I can't upload my jpg photos to this forum, please chime in!

https://imgur.com/a/CRfGcCt

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retiredVTT
Posts: 5417
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Location: Bedford, NS,CANADA
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Re: Hollein Introduction F5J Build Update

Unread post by retiredVTT » Thu Jan 21, 2021 1:13 pm

I believe the photo size limit is 2 MB each...
Bill
HEFA #5
MAAC #13708

DoverSail
Posts: 50
Joined: Thu May 07, 2020 4:18 pm

Re: Hollein Introduction F5J Build Update

Unread post by DoverSail » Thu Jan 21, 2021 3:18 pm

Ah, I see. I’ll have to get out my Polaroid camera...

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