Hollein Introduction F5J Build Update

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DoverSail
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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: 164
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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
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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
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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...

DoverSail
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Re: Hollein Introduction F5J Build Update

Unread post by DoverSail » Mon Feb 01, 2021 11:14 am

Alright I finally figured out how to re-size these photos into teeny tiny little sub-2MB files!

This constitutes the latest progress on my Hollein Introduction F5J build.
Snow.jpg

The wings are complete. They join together using ingenious little plastic U-shaped retaining clips, which are pushed into a slot under the wing and hold a retaining screw in place.
Outdoors2.jpg
I have finished with the brush-painting and grain-filling on my fuselage. Now I have a spray-paint can which I will use to apply two or so coats to give a nice brushstroke-free finish. Once the fuselage is painted to satisfaction, the electronics are ready to install, and we will be off to the races (pending balancing etc).

I am really pleased with the appearance of this Oralight translucent white and violet.
WingDetail.jpg

More to come soon! It shouldn't be long before the Introduction is tearing up the skies at its Vne =15kph any weekend now!

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retiredVTT
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Re: Hollein Introduction F5J Build Update

Unread post by retiredVTT » Mon Feb 01, 2021 1:02 pm

Wow..looking good, like this outdoor shot...!
Attachments
DoverGlider.jpg
Bill
HEFA #5
MAAC #13708

DoverSail
Posts: 164
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Re: Hollein Introduction F5J Build Update

Unread post by DoverSail » Mon Feb 01, 2021 1:29 pm

Thanks!
You really need to have the plane next to a person to get a sense of the scale.It is not as large as John and Andrew's Pulsars, but it is still close to 3M in span.
Outdoors_small1.jpg
This photo was taken on a speaking tour in Australia, apparently. Literally no amount of editing will make it show the right way up here.

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retiredVTT
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Re: Hollein Introduction F5J Build Update

Unread post by retiredVTT » Mon Feb 01, 2021 5:36 pm

It's "upright" when I click on it ..! Very colorful ...!
Bill
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bdg
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Re: Hollein Introduction F5J Build Update

Unread post by bdg » Mon Feb 01, 2021 7:34 pm

Very impressive! Looking forward to seeing it in action!!!

What is the wingspan again? 3m? Impressive indeed! And what other specs? Motor ESC? Battery? All-in weight?

Brian

DoverSail
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Re: Hollein Introduction F5J Build Update

Unread post by DoverSail » Tue Feb 02, 2021 8:15 am

bdg wrote:
Mon Feb 01, 2021 7:34 pm
Very impressive! Looking forward to seeing it in action!!!

What is the wingspan again? 3m? Impressive indeed! And what other specs? Motor ESC? Battery? All-in weight?

Brian
Thanks Brian!

The wingspan is 2.86M.

It is covered in Oralight translucent white and transparent violet. The AUW should be somewhere around 950g; so far it appears to be on track to reach that.

The electronics are as follows:

RX: LM0052 Lemon DMSX with integrated variometer telemetry
Battery: 3S 1300mAh Tattu LiPo 75C
Servos: EMAX ES3302s for flaps (2 in wing) and rudder/elevator
ESC is a Mantis 40A driving a Hacker A20 22L EVO brushless, and the prop is a folding carbon 11x6 with a turbo-spinner.


I am basically trying to get my final coat of finishing paint on the fuselage; I tried spray over my previous brushed coats but the spray looks worse; it either speckles or runs, seemingly there is trick to this but it sure is taking a lot of time! I have to sand this latest botched coat back off and try again. I may see if I can obtain the help of one of the painters where I work.

Then I just need to pop in the electronics and I should be ready to fly, assuming everything balances as it should!

I was surprised to see that my previous post was included in today's newsletter. A really nice surprise! Thanks Al!

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