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Fullfilling the dream... the ultimate rubber powered airplane

FAI-F1D

Free Flight Indoorist
#81
Next I built out the vertical stab. The outline is .004" Boron. Really challenging to use if you don't pay close attention, but I'm pretty comfortable using it.
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Here's the stab and rudder laid out together waiting to be covered:
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And on the covering frame:
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And a tip on building stabs:
 
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FAI-F1D

Free Flight Indoorist
#82
I built out the motorstick part of the way at this point. Seam glued up...
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Next the polyamide tubes are added with the carbon wing posts:
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I went ahead and finished out the stub boom and tailboom. The stub and boom get a strand of .004" boron top and bottom. I left the borons on the stub overlength so that they could stiffen the connection to the motorstick.
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I now cut out the wing. The bracing jig was already in place on the table so I could go straight there...
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And here it is with the dihedral breaks glued and attached to the wing posts:
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With the bracing wires installed, I could lift the wing free of the frame (had to remove all those support sticks first):
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And into the box for safety:
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And a tip on adding bracing hardpoints:
 

FAI-F1D

Free Flight Indoorist
#83
Next up...the stab...

The rudder is attached to the boom. This is straight out of Steve Brown's playbook, except that there will be adjustable posts on the trailing edge for incidence tweaks (more on that later):
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Posts installed, invisible bracing wires in place. Also, the leading edge is hinged...
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All done:
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And the stab lock loosened to show that it really does hinge (but not nearly as well as I'd hoped--it won't go past 45 degrees without heavily stressing the entire stab):
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FAI-F1D

Free Flight Indoorist
#84
Time to build out a motorstick...there's a lot on my website and youtube channel about this stuff so I won't belabor the point:
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Side view. Note much heavier bracing wires used on the stick:
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FAI-F1D

Free Flight Indoorist
#85
And with that, I could finally assemble the model:
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I tossed the prop hub on for ballast, and got a test glide. Oh. Wow.

The prop was just too heavy and I couldn't use it, so I loaded up the 25.5" prop from the Hourglass II. After adding some stab incidence, it stopped trying to commit suicide, but it still needs work. Remember that adjustable indidence thing? Yeah, the boom doesn't go on straight, so I'm no out of up elevator travel. So...time to remove the stub boom and reglue it so the droop goes away.
Anyway, a somewhat haulting flight:

So where next? Well, fix the incidence, add *more* bracing wires to the wing, and fly it on Saturday. If all else fails, boron on the wing will end the stupid.
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Even if it doesn't set a record I'll consider it a success. This is the most majestic flying thing I've ever built, and it's still flying like it's drunk! Wait till we get it happy!
 

FAI-F1D

Free Flight Indoorist
#86
I added some more bracing wires to address the unacceptable flexure of the wing spars. Also re-attached the stub boom to provide additional stab incidence. Now we're getting a flight patter that looks relatively promising:
 

FAI-F1D

Free Flight Indoorist
#88
The Hourglass III made its first public outing. It looked absolutely stunning in the air.
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Hopefully some of the better videos will make their appearance, but I at least got something to capture a little of what was happening. Including a really, really bad, scary, incident (but not the worst). She did come home ok though.


I'm seriously considering building a second wing. This one seems to just be too fragile. I can afford some weight increase - cruising at 26 rpm leaves me with a LOT of room to tweak things. That said, gonna go a little smaller on the prop. I think a 30" VP prop is where the best performance will emerge. Also go back and look at that first photo. Look closely at the wingtips! Yes, that's seriously like 10%+ camber in the tips on a wing that's 5% camber across all the rest of the span. Yeah, that's like watching a plane flying across the sky with fuel just pouring out of every exposed surface. It don't work. It's like driving around with the parking brake on. One could make the argument that there's a little more performance to be had...

Also, some more shenanigans...Nick Ray's crazy ministick!

And I bested my F1R national record of 28:06 with a 28:12. Not turning in the paperwork for 6 more seconds, though. I will, however, be tweaking things soon to take advantage of the 4 minutes worth of turns I landed with, because hitting 30 minutes in Cat I with such a small model would be freaking awesome.
 

FAI-F1D

Free Flight Indoorist
#89
Hope has been working very hard on her Hourglass II. I don't know of any other women who have attempted such a thing.

Here she is bonding a prop outline to its spar to achieve the necessary helical twist:
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And here's her wing build out, still on the jig, next to a covering frame loaded up with OS film:
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At this point I ran off to find an appropriate box. I'd been hiding this one in the attic for use with a DLG transportation, but that's been nixed.
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Jim Walston of Walston Retrieval Systems build this awesome box for transporting F1C glow free flight models. Unfortunately I had to knock all the nice fittings out of the way. Here it is getting a test fit from my own Hourglass II:
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Another view:
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At this point I had a bit of inspiration. There's a lot of room there...this wing barely enters the top half of the box. Hmmm....
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Time for some rolling of goodies:

Here's Hope's motorstick with wing posts installed:
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And her wing bracing jig:
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And with a wing on it, posts being attached (having skipped the massive bit about covering it):
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And skipping one more absolutely massive step (yes, I've got video!), Hope has a fully braced wing that's super rigid and super awesome!
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Back to that crazy stuff about the box, um, wow, this is awesome! Yes, both Hourglass IIs actually fit in the box with room to spare!
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FAI-F1D

Free Flight Indoorist
#90
Oh you thought it stopped there? Nope, check this out:
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3.4 g as shown. A little heavy, but definitely light enough to make 40 minutes with room to spare. Bravo to my awesome wife!
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And the cool part, maiden test flight:
 

Rclements

Junior Member
#91
That looks awesome. I'm going to have to build a box, and your wooden one looks awesome!
I gotta say, the model stand looks really nice too!:cool:
What size carbon are you using for the wingposts?
What weight do you use when bracing the wires too?

Ross
 

FAI-F1D

Free Flight Indoorist
#92
That looks awesome. I'm going to have to build a box, and your wooden one looks awesome!
I gotta say, the model stand looks really nice too!:cool:
What size carbon are you using for the wingposts?
What weight do you use when bracing the wires too?
Mind you, I didn't build that model box. It came out of Jim Walston's estate. Super nice and had never actually been used. It was set up for F1C models originally.

I'm just not sure about that model stand. :p

0.028" cf tubes from CST. They're super nice.

So far I'm only using a piece of tape on the end of the wire and then pulling it tight by hand. I need to start using weights..probably 1g would be sufficient. Maybe 2.
 

Rclements

Junior Member
#93
F1C looks awesome, albeit rather noisy and terrifying!

Is .028" a bit on the small side for a model so large? I'm getting ready to start mine, I guess I better build a bracing jig soon.

Is there much of a difference in weight with the .001" bracing wire vs the .0003"? I have a roll of the bigger stuff and would rather not have to buy some more if there isn't much of a difference.
 

FAI-F1D

Free Flight Indoorist
#94
F1C looks awesome, albeit rather noisy and terrifying!

Is .028" a bit on the small side for a model so large? I'm getting ready to start mine, I guess I better build a bracing jig soon.

Is there much of a difference in weight with the .001" bracing wire vs the .0003"? I have a roll of the bigger stuff and would rather not have to buy some more if there isn't much of a difference.
So far I haven't run into issues with the thin carbon posts. The bracing wires take up a significant portion of the load, so there's not a lot of deformation. On an unbraced model this size, were that even possible, you'd definitely need much thicker wing posts.

I'm concerned that .001" wire would add too much weight. You're going to have something like 15' of the stuff on that wing, maybe more. I don't know what that works out to in terms of weight, but my ocd would be really going off. ;)

Agreed on the noisy and terrifying aspect of F1C. I've been around them a little and they are LOUD and extremely unforgiving. They're also incredibly cool, but at $2k/airplane, it's definitely not a poor man's sport.
 

FAI-F1D

Free Flight Indoorist
#95
It's been a while y'all! Whelp, we went to Lakehurst and we flew things!
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Yes, Canada's Dmytro Silin brought his own 50" span Unlimited along!

And so we got down to flying. Dima was only able to be there for the first weekend, but we had spectacular conditions and we flew. And we found out just how tough this can be.

Dima in particular folded his model up several times and came away unsuccessful in his effort to join the 40 minute club. He had it made on several flights but steering issues kept him from making it. His best was 37 minutes. He'll be back later this year for another go at it.

Regardless, this is a beautiful model. Dima is a true craftsman. He's actually done 40 minutes before, but it was a practice session many years ago and so wasn't an official contest flight.
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Dima came away with a new Canadian Cat IV F1D record of 23:29 with his excellent new model:
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Nick Ray did a spectacular 33 minutes in F1R for a new national record, but it came at a high cost. Whoopsies!
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Don't worry, he's already got it fixed. And now he believes me about not winding near your plane.

I had an opportunity to scare the snot out of myself. This is my original Hourglass II cruising under the center catwalk about 25 minutes into a flight.
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Unfortunately the motor blew less than 10 minutes later and it was on the ground at only 37 minutes. I also had two other flights of 39 minutes, once thanks to a poor climb, and once thanks to my tucking the prop 50' up in my umpteen botched steer.

Finally about 5 in the afternoon of day 2 I put mine up again to about 140' and pulled off a clean flight of 46:06, my first ever 40+ minute flight.

While my model was on its way down, Hope launched her Hourglass II production model for a spectacular climb straight to the center catwalk. Her climb ended only about 5' short of the girders, nearly 170' up. There was very little drift and only a quick nudge was required at the end of the flight to avoid a scrapped arresting cable (yes, like one from an aircraft carrier). Hope deadsticked in for a personal best of 35:57!
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You may have noticed I haven't mentioned a thing about my big Hourglass III. Well... I found out my propellers weren't up to the task. I was stuck between that razorblade of a low enough pitch to get the model climbing well would tuck the blades in cruise, but a high enough pitch to prevent that required so much launch torque for a climb that the blades would flutter on launch. Uh...yeah...not good. I have a lot to learn. That said, there is video, and it will be forthcoming. Anyway, that's why I resorted to my backup.

So...that's the summary for our first weekend at Lakehurst. I'll throw up the second weekend's stuff later. ;)

Here's a video to hold you over in the meantime: