My first F1D

[Olbill]

Sometimes i "know" a fact; it has come from a reputable source but I don't get it. It may take some time for the explanation to come clear in my mind and to sink-in. Perhaps anther experience triggers the information making sense.

Exactly. Then one of two things are likely to happen. Either it dawns on you what they are talking about or you find a better way.

[Skymon]

What did I learn?
If I look at the new processes I learnt as I built the F1D, then I don’t see that many. My build log of the F1R is filled with lessons learnt, while the F1D is less so.
The F1R was a lot harder, the materials are fragile, the dimensions are smaller and the whole thing is critically based on weight reduction.
The F1D was more a lesson in neatness and control. The min weight is achievable if you take care and the materials are all much more robust than F1R. As a result I think the F1D is a model that anyone who's got some experience with indoor models can build.
I approached the project with trepidation, there is a lot of info on the web about F1D. It’s the big international class, there’s a lot at stake. The indoor flying crowd are masterfully adept at sharing information, there is no attempt to hide the latest developments; everyone shares.
This plethora of info makes it a little intimidating to actually get going. Which route do I take?
In the end I just chose a nice looking plan that had been published. It was reasonably up to date and I like the shape.
There were a few things on the plan that I wasn’t sure about, I ignored them and did something different, usually after asking for the advice of the whole F1D crowd.

The first thing I learnt is something I always champion and yet I found it hard. Just get stuck in.
Make something and if it’s not to your liking, do it again.

Starting with flying surfaces I learnt that masking the ribs off when spraying adhesive helps. The film finds its own way and those diagonal spiders web creases tend to be less prevalent. I needed to make big frames, these need to nice and rigid. Gluing a handle to the part to be dropped on the film really does help, just remember to remove it after.

Of the surfaces I covered the wing was fine, the stab is flappy and saggy and I will probably make another, it’s overweight anyhow.

Regarding rolled balsa tubes I applied lessons learnt in the F1R construction. A tip from Bob Bailey meant I switched to Duco rather than UHU. He mentioned that it grabbed better. It did.
Lining up posts in all directions is important to me. I love a bit of neatness. I took my time here and teased the holes in the stick to make sure I was 90 degrees up and 90 degrees along when attaching wing posts. Use a square and check and check again.

Adding boron to everything was intimidating but actually not too much bother. It isn’t a great feature as I see it popping off here and there, so it’s a constant task to check each and every addition and glue down any that come loose. Hopefully as carbon fibre increases in use the boron will decrease.

I hit my usual problem, I built too robust, especially in the prop area. There’s a lot of work in a prop and I wanted to make sure it wasn’t going to let me down.
In the end it was pretty heavy and I have started another one, as I did for F1R. Took me four goes there…

I have added the web up the front and also added small tissue wraps around the motor tube and boom ends to stop them flaring on insertion.

That's about it.
Have a go.

I added a picture of my kitchen that I have been building along side the F1D.
I don't expect the kitchen to fly.
Si

[Uggy]

Hi Skymon;

Thank's for the informations you keep sharing. This is very helpful.


> Starting with flying surfaces I learnt that masking the ribs off when spraying adhesive helps.

Can you please describe a bit more how you are masking ribs ?

> A tip from Bob Bailey meant I switched to Duco rather than UHU. He mentioned that it grabbed better. It did.

Do you mean for all parts, or only for rolled balsa tubes with a possible different stress ?

I have read an article from Bob in 2014 saying "I now use Duco or UHU thinned with an equal volume of acetone for
most joints including attaching boron; it has excellent contact strength almost from the instant of making the joint"
So I'm a bit confused.. and need to know if I have to go for Duco (which I will do if you confirm it's better)

So jumping on that to have experts thoughts/confirmation on current formula for Duco/Uhu


Thank you

[Olbill]

I use Duco for almost everything.

[Tmat]

I use Duco for almost everything.

Toothpaste Bill?

Tmat - well, maybe not everything

[Skymon]

I masked the ribs by placing a couple of pieces of paper over each one.
I cut a some strips about 15mm wide, folded them on the centre to make a V shape, turned them over and placed over the ribs.
By placing one over the other I can make a rudimentary extendible mask.
Simple as that.

I found DUCO to grab better than UHU or Humbrol.
All of them work though, I built my F1R with Humbrol.
DUCO seemed to grab quicker and set faster.

I mix 50/50 with acetone for most things.

Regards

[Uggy]

Hi Skymon

OK, I was thinking at first you were masking side of the ribs, keeping top of the ribs exposed to adhesive. Seems not the case.
Not sure ton understand the process here, you spray adhesive on LE/TE only, and then how do you glue film to ribs ?

Thank's!

[Skymon]

Hiya
The film sticks to the outline of the wing/stab/fin.
If you've not covered an indoor with OS film before then I'd suggest you have a look at the videos on YOUTUBE that explain the process.
I've not really mentioned it on this build as it is well covered in detail on other threads and in INAV and online.

Here's Josh showing how it's done.
https://www.youtube.com/watch?v=TqR7_C1wO88&t=537s

S

[Olbill]

I don't glue the film to the ribs.

[Uggy]

Hi,

I have covered in the past with Y2K and 3M77 (and was gluing the ribs )

The other articles [1] I have read about film gluing (and the Josh's video too) do glue the film on the ribs too.
This is why I was surprised some are masking ribs and asked for more details on this.
I learned now it is possible to not glue ribs (without impacting flight). Thank's for sharing. That's indeed new to me. I will look deeper on this now.

[1] Kang / Mark Bennett / Ray Harlan

[Skymon]

I saw someone somewhere say they masked ribs and I also saw a picture of someone using the post-it note reference tabs to do it.
I think possibly on the facebook groups.
I pondered why they might be doing this and then when I made a poor attempt at covering my stab I realised that a saggy covering may benefit from sticky ribs, but a more even one would actually be hindered because it would be constrained on contact.

I think if you cover loose, and some people do, then the rib contact would hold the surface shape together better.
But if you cover tighter then the ability to move slightly on the ribs helps make the surface more even.

It might be worth a topic on it to get input from the real experts rather than me and my paltry single plane ever opinions

[Uggy]

Thank's for the additional informations shared.

[Skymon]

I flew the F1D for the first time a couple of weeks ago at TVAC in Windsor.
My first powered flights were not great.
I struggled to get the prop on and had to modify the hook shape to allow me to get it in. A lesson learned there.
I popped some rubber on and let it go.
Power dive. Adjust, more power diving.

My boom was sagging.
Not the boom itself, but the joiner.
I'd used a stump that was way too small and too weak.
This is a critical joint and my efforts were not up to the pressure.

I have since removed the weedy plug and replaced with a mighty plug.
The original 14 though wood was replaced by some twice as thick.
I figured that this is a small component and I'd rather the plane flew than didn't.
I created the plug and fitted it to the motor stick, then carefully sanded it to a nice fit on the boom.
I marked a little alignment mark when the fin was vertical and I had what looked like the correct tail tilt.

Now I wait for the second opportunity to fly.

The day at TVAC wasn't a complete washout, I managed to beat my F1L record and sneak just over the nine minute mark without gong anywhere near the ceiling.
I was being precious because I was testing three new wings and I wanted to be damage free.


Happy flying
Si

[Skymon]

I've flown this plane twice now since TVAC and I have made some progress each time.
My new plug insert has proven durable and works.

I flew it at the NATS in September and didn't manage to get over 4 minutes.
I broke two motors in the process and had no real idea what I was doing, but I enjoyed myself.
This place was a CATII, just, but I was nowhere near the ceiling.

Then I flew again on Sunday back at TVAC.
I have made a slightly smaller 406mm diameter prop that seems to work well.
I am trimming on a fixed pitch hub for starters.

I managed to crack 6:30 on half a motor without going near the ceiling, which in TVAC is quite a popular resting place for planes.
I had a bunch of help from Bob Bailey and have a lot of building work to do.
Bob spotted my CG was off, the plane wasn't recovering well and was flying as though it was stalling, but not stalling. It looked weird.
A piece of blutak was added and the flight path was transformed.

I flew on a half motor I had and put on a safe 500 turns launching at 15g/cm.
I got two flights at 75% altitude, one at 6:30 and one at 6:28.
I have just over 100 turns left on, so I need to tweak motor size.

I am now off to build a more robust boom and also to build some more stabs in an effort to drop the mass at the rear.
The long moment arm of the boom means if I drop a bit of mass there I can get rid of the blutak blob.

My CG is well marked now and I will be making adjustments in readiness for my next outing.
I am also looking at making up a few VP hubs to enter that area of adjustment.

Si

[Skymon]

I have had F1D flying session number three and things are progressing.
I am flying half motors with a spacer.
The big change this time was that I have a couple of Treger VP hubs. The idea of this session was that I was trying to get a handle on how these worked and how to adjust and set them up.
I was flying on TANII rubber of 1.265 g/m and I spent the whole day flying, adjusting and flying again.
I broke the monotony with a few F1N flings, but in the main it was an F1D day.
I learnt a lot about how the hub works, saw the RPM change from high pitch to low through the flight.
I struggled to get to the ceiling, probably OK on a half motor, but I was after duration :0
I had a number of issues with the airframe that I worked through during the day. I had the help and assistance of Bob Bailey and Hans Staartjes.

The first issue that revealed itself in the early flights was the bracing wire.
Far too slack, the whole plane had a banana shape during fight, even with minimal torque. My post was unadjustable, so I added another piece of wood on the side and then moved the wire up there. During the day the wire cut down through this extension piece and lowered my tension – I fixed it by adding a tiny piece of tissue to the top.
Now I had a motorstick that had a tiny bit of up curve on it unloaded, add a wound motor and it was straight again. My flights improved considerably, I was adjusting the preload and prop pitch as these fixes were happening.
By flight four I had a decent flight path, by flight five I had enough torque to be seeing an obvious high torque position on the prop blades during launch.
I was launching at 15 g/cm and almost climbing. I started to add turns and torque.
Flight 9 was 520 turns on and launched at 25g/cm. The prop was turning 44 RPM at launch and then turning up to 56 as the torque dropped.
I landed at 5:26. My previous best on 0.2g of rubber was 6:30, so I thought I had a good chance of a new PB
Two more flights changing the top and bottom stops and adding more turns and torque.
Flight 11 had 520 turns, 25 g/cm and saw the plane get to 6:14 with the VP running 44 RPM until 1:20 then transitioning over to 55 RPM for the cruise, dropping off after that before landing.
Flight 12 had 560 turns, 27 g/cm and with pre-load adjusted the transition started at 1:38. I was up to 6:39, a new pb, yay!
I then flew a number of flights at 580 turns and 30 g/cm until I was achieving 6:50.
Adding a few more turns to try and break seven minutes broke my motor. Oops.
I had a duplicate motor, so I was off again, but this motor felt slightly less powerful. Within a few flights I was at 6:20 and 600 turns, more than I had ever got on the last motor.
Then the plane started to act up – at 32 g/cm launch it was floundering about and not climbing. The flight was erratic and it just looked in trouble.
Bob had a look and my prop bearing web was folding under high torque, introducing lots of down thrust.
I used spare balsa to make nice new web out of some harder 1/32 that was kicking about in my scraps box, but by now it was almost time to go.
I wound for one last flight just to check the web would hold – it was all OK. In all the flights I had never got more than ¾ of the way up to the roof, I need to work on the climb section, this will involve either rubber or prop changes, or maybe both…
I got the new F1N out for a few warm up throws and then packed up.

Back at home I took stock and reviewed where I was. I feel my airframe is not quite right for the usual UK low ceiling flying and my plane is overweight at 1.6g so I have a program of serious building ahead of me. The model plan I used was a Treger design for high ceilings, it’s made for a long thin motor and a fixed pitch prop. I have ordered a bunch of new wood and I will be making new motor sticks, booms and surfaces in order to get stronger, lighter parts. As previously mentioned, a lighter stab is first on the board. I have built a new one but it came out 15mg heavier, so no improvement.

I also need to make a selection of props and finish off my carrying box…

Onwards and upwards!
Thanks for reading.

S