Show us what you are working on..

[Yotaman1985]

Thanks for the explanation Wayne

 

[Yotaman1985]

Had some time tonight to try glassing the Z1 fin. Ended up doing two layers of .75 oz cloth on both sides and some peel ply ontop of that. Then I bagged it with my wifes food vacuum sealer (dont tell her... ). Seemed to work alright and looks decent to my extremely untrained eye. Lol Ill let it cure tonight and try unwrapping/removing it tomorrow

 

[Doc J]

Thanks Doc,

I may go that route for simplicity although I dont have ballast so the tube wont be used anytime soon. Ill cross that bridge when I eventually get some ballast for it. I feel like I remember reading that this glider does best if the wings are loaded up first and then fuselage tube, does that sound right?

Hey Yotadude:

As if you put ballast in the wings, you increase the moment of inertia, thus making the ailerons more and more sluggish as you add weight. The closer you can keep the ballast to the central (longitudinal and latitudinal) CG location, the better. Ergo: The fuselage ballast tube is always better.

Sometimes, I think the competition F3f guys like the wing ballast, as it acts as a kind of 'gyro', decoupling and dampening the effects of their (over) control movements. It's certainly true of the serious DS community.

Cheers,

Doc.

 

[Yotaman1985]

Well, results are in and they look promising! The fin turned out alright, maybe a 5 out of 10 so not too bad for my first try. I had some issues with air bubbles around the harder corners even though I had angled them. I think this is due to me CA'ing the carbon down prior and causing it to be stiff. Same thing happened at the edges of the fin where the carbon was as it was stiff and didnt let the glass wrap around the edge causing a void.

On the plus side, the fin is very ridged and light so I think this is the way to go. Have enough balsa to make a few more and those should turn out a bit better although this one is totally flyable if needed.

 

[Wayne]

Looks great for a first try! I'd totally fly that.

You might allow the corners to be a bit wetter going into the bag to seal the edges, and then sand them down a bit after they cure.

What are you using for resin?

 

[Yotaman1985]

Looks great for a first try! I'd totally fly that.

You might allow the corners to be a bit wetter going into the bag to seal the edges, and then sand them down a bit after they cure.

What are you using for resin?

Thanks Wayne,

I have some Z-poxy finishing resin that I am using. Part of the problem for this fin was I didnt mix up enough and was scraping the cup trying to get every little bit I could to wet it out. Ill make sure to mix plenty next time and make sure the edges are wetted out well

 

[Wayne]

Did you use a mylar sheet or anything? I didn't see it in the photos. One of the tricks a buddy did was sand the top of mylars where he had to deal with a lot of curvature.

 

[Yotaman1985]

Did you use a mylar sheet or anything? I didn't see it in the photos. One of the tricks a buddy did was sand the top of mylars where he had to deal with a lot of curvature.

I did not use mylar. Is that supposed to help push the glass down into the corners?

The other issue I had was the bag lost vacuum (the photo of it bagged has air bubbles in it from the vacuum leaking). It looked really good when I first vacuumed it but slowly lost it. We have had issues with these bags doing this with food too so I think I am going to order some new vacuum bags to try and hope that helps.

 

[Yotaman1985]

Attempt number 2 is under way. Wetted it out a bit more and added the carbon with the fiberglass. Got some new vacuum bags also which seem to be holding vacuum better. We'll see how it looks tomorrow

 

[purview]

turned out that the bird has a lead problem. hope to fix the electric conversion with everything (it should be) in balance...

 

[G-man]

Working on reducing the HOWLING NOISE

Last Fall, test flying my scratch build WANDERER-99 wing on my store-bought PRELUDE fuselage,
I noticed the plane made a "Halloween Howl" sound when pouring on just a little bit of speed.
This was repeatable.
Next flying day, flying buddies said "That's not a HOWL, sounds more like an AIR RAID SIREN."

My first move was to close up the gap between the fin and rudder, visible in photo 1.
Now it's a tape hinge, but the sound is still present.

My current theory is that it's caused by "micro fluttering" of the tip panels.
The inner panels of this design are quite hefty, incorporating 3/4 inch spruce spars, top and bottom, with shear webs.
The outer panels are quite sparse, single lower spar only, presumably to lighten the tips to indicate thermal activity.

I removed the covering and installed a top spar of 1/4 x 1/4 balsa, and I'm pleased about how much the tip stiffened up.
Now, how much more structure to add?
1. Extend the three turbulator spars from the inner panels.
2. Install diagonal braces between the spars an the leading edges.
3. Combination of 1. and 2 .
4. Add no more structure but cover with TopFlite SUPER MONOCOTE, the covering material most likely used by the designer.

Right now I'm inclined to go with #4 to finish the rehab quickly an still keep the tips as light as possible, as designed.
My wing was originally covered with Value Hobby Neucover, a low-temperature film.

Any other ideas or suggestions?

 

[Yotaman1985]

I un-bagged fin #2 this morning and it turned out a bit better than the first but still not great. Maybe a 7 or 8 out of 10. Still have some voids on the edges but much smaller and more managable than the first. Peel ply came off easily on one side but I had an issue with the other as the fiberglass had been completely wetted out and I could not seperate the edge of the fiberglass from the peel ply. Ended up tearing some of the fiberglass and pulled up a corner on the fin. CA'd it back down and it should be fine but a lesson learned about peel ply. Gonna wait until this evening to do the final sanding so the CA that wicked into the edges can cure. The weight of this one is 15 grams all trimmed up and ready to fly.

 

[Wayne]

Working on reducing the HOWLING NOISE

Last Fall, test flying my scratch build WANDERER-99 wing on my store-bought PRELUDE fuselage,
I noticed the plane made a "Halloween Howl" sound when pouring on just a little bit of speed.
This was repeatable.
Next flying day, flying buddies said "That's not a HOWL, sounds more like an AIR RAID SIREN."

My first move was to close up the gap between the fin and rudder, visible in photo 1.
Now it's a tape hinge, but the sound is still present.

My current theory is that it's caused by "micro fluttering" of the tip panels.
The inner panels of this design are quite hefty, incorporating 3/4 inch spruce spars, top and bottom, with shear webs.
The outer panels are quite sparse, single lower spar only, presumably to lighten the tips to indicate thermal activity.

I removed the covering and installed a top spar of 1/4 x 1/4 balsa, and I'm pleased about how much the tip stiffened up.
Now, how much more structure to add?
1. Extend the three turbulator spars from the inner panels.
2. Install diagonal braces between the spars an the leading edges.
3. Combination of 1. and 2 .
4. Add no more structure but cover with TopFlite SUPER MONOCOTE, the covering material most likely used by the designer.

Right now I'm inclined to go with #4 to finish the rehab quickly an still keep the tips as light as possible, as designed.
My wing was originally covered with Value Hobby Neucover, a low-temperature film.

Any other ideas or suggestions?

#2 should do the trick even with thin film. It is pretty easy to do also. Don't let them touch the film at the top of the wing.

#4 might be the trick, but may require the entire wing be covered in the thicker film.

 

[G-man]

Thanks Wayne. I think I'll go with
2. Install diagonal braces between the spars an the leading edges.
I have enough ORIGINAL SUPER MONOCOTE to cover the tips, but not the whole wing.

// Dave

 

[Doc J]

I un-bagged fin #2 this morning and it turned out a bit better than the first but still not great. Maybe a 7 or 8 out of 10. Still have some voids on the edges but much smaller and more managable than the first. Peel ply came off easily on one side but I had an issue with the other as the fiberglass had been completely wetted out and I could not seperate the edge of the fiberglass from the peel ply. Ended up tearing some of the fiberglass and pulled up a corner on the fin. CA'd it back down and it should be fine but a lesson learned about peel ply. Gonna wait until this evening to do the final sanding so the CA that wicked into the edges can cure. The weight of this one is 15 grams all trimmed up and ready to fly.View attachment 22529View attachment 22530
View attachment 22531

Hey Yota - and anybody else who may see this:

You know that you are using E-glass there, right? It's not as strong as S-glass, but it still weighs the same. The "E" normally denotes "Electrical," and this type of fabric is used to make multilayer PC boards. E-glass can often, but not always, be identified by a coloured thread —usually black or red—woven into the fabric.

Another point is that E-glass is often not sized (Chemicals added) to allow the resin to wet out easily. The PC board manufacturing process depends more on tons of direct pressure to completely wet out the fabric than the atmospheric resin transfer method (RTM), brush stippling, or rolling.

Id Est:

S-Glass vitals:

S-glass is a high-performance glass fiber, distinguished from E-glass primarily by its higher silica content. S-glass typically contains the oxides of silicon, aluminum, and magnesium with the following mechanical properties:

• Density: 2.53 g/cm3 (157.9 lb/ft3)
• Tensile strength: 4,600 MPa (670 ksi)
• Modulus of elasticity: 89 GPa (12,910 ksi)
• Percent elongation: 5.2

Compared to E-glass, S-fiberglass offers much higher tensile strength and (Young's) elastic modulus and about 10% greater stiffness. These qualities make it suitable for use in demanding applications, such as the aerospace industry.

Also, some advice from a long-time sticky finger guy:

It's a good idea to cut the glass close to the size and shape you need before wetting out or, alternatively, to cut the extra glass off when it's still wet. Extra fabric along or around the edges will often cause the resin to wick away from the part you are glassing and might even cause air pockets or voids. To avoid this problem, the natural but not so good thing is to apply more resin than is needed, which results in a heavier part.

Cheers - and looking goooood!

Doc.

 

[Yotaman1985]

Thanks for the info Doc. The fabric with the red stripes is the peel ply, not the actual fiberglass but I will definitely use that info in the future as the fiberglass I have just came from amazon.

Got the 3rd fin un-bagged today and it turned out great. A solid 9 out of 10. Was able to get the glass and carbon to wrap around all the edges this time.

Got the Z1 balanced and ready for a maiden. Just need to tape the carbon covers on and shes ready. Came in at 18.5 oz RTF weight which Im pretty happy with.

 

[TyFlies]

@thenated0g There was a 48" molded wing called the Passaj (Aeromod ) It comes apart at the center line and can be packed small We have one flies great! With your tools it should not be too hard to put something together.

Passaj CG?
I’m resurrecting an old Aeromod Passaj slope wing that I got from someone else. Do you know the recommended CG? This one has a tow hook at about 120 mm back from the nose, but that seems pretty far forward as a CG , just looking at it.
Searching the internet for CG info, and not coming up with much, but it did lead me to this 2023 post in this thread.
Thanks for any info!

 

[Doc J]

Thanks for the info Doc. The fabric with the red stripes is the peel ply, not the actual fiberglass but I will definitely use that info in the future as the fiberglass I have just came from amazon.

Got the 3rd fin un-bagged today and it turned out great. A solid 9 out of 10. Was able to get the glass and carbon to wrap around all the edges this time.

Got the Z1 balanced and ready for a maiden. Just need to tape the carbon covers on and shes ready. Came in at 18.5 oz RTF weight which Im pretty happy with. View attachment 22538View attachment 22539View attachment 22540View attachment 22541

Peel ply...yaaahhh...well anyway I hope it's good advice.

Doc.

 

[purview]

the balance lead was glued in place. had to do another cut for the e-conversation. then an engine mount out of plywood was cut and the positioning of the nose (as best as the design allows) worked out. fuselage tends to overlap the spinner, ...better not to use a perfect circle in front, right?

 

[Wayne]

Wondering if you can cut some more back, then put some masking tape over the fiberglass and glue on some chunks of balsa and sand in a nice shape to meet the spinner circle? Just an idea.