Instructor

My Feedback: (16)

Hi RCISFUN,

I checked my wings and I got the same readings as you did. I thought you would like ot seethe fuel tank I made for my Formost. It is made from 6 oz glass cloth and EZ Lam laminating epoxy resin.

Warwick Laken

I measured mine in the same way as RCISFUN and got 19mm on both wings. I joined the two wings together with a wing tube and placed a straight edge across the wings and got a measurment at the joint of 4mm sowing a positive dihedral.

SpiderJets

Here is a photo of my first set of wings...

SpiderJets

Here is a photo of my second (=new) set of wings, same findings.... (I hope you can see it like I did, it's taken with a pocket camera, not w/ a wide angled lens)...

SpiderJets

And now with joining the two wing panels with the alu tubes, and placing them flat on the table...

I notice the wings are almost flat on the table at the bottom side (maybe some 10 mm "V" at the bottom) and MUCH more "inverted" V at the top wing side....

It's like the whole "transition" from the wing root airfoil to the wing tip airfoil is taking place on the TOP side of the wing ; usually it is in airplane modeling the other way around ???

SpiderJets

Did we eliminate an eventually intentioned dihedral by inserting a single wing tube ?

If so, the manufacturer MUST change this design in this respect as well and incorporate the design of the positive dihedral in the WINGS and not in the design of fuselage section...
In fact, it is not logical to have an (faulty) anhedral design in your wing and eventually trying to eliminate/correct this by overcompensating the angle in the design of your wood construction in your fuselage (if so..). Not really a proof of proper airplane designing skills... [&o]

Also, during manufacturing, there seems to be no sufficient QC or at least some wing tube building templates for assuring that all wings/wing angles are identical during production. Different owners have different dihedral measurement readings, even on comparing their own single L+R set ?? [X(]


(See previously posted photo, the L+R tubes in the fuselage are not aligned in the vertical (and horizontal !) plain but also indicate some intention of (corrective ?) dihedral ? Am I right making such conclusions ?
It would be interesting to see a brand new kit, insert the wings on that one and see what the dihedral/anhedral is without ANY modification done to the kit so far. Anyone... ? )

SpiderJets

Well.... the only good thing about this is that I did not notice any bad flying tendency due to the anhedral, and it flew very stable throughout the entire speed envelope...

That's at least something positive (and absolutely vital !), Richbran ! [8D]




PS. Thank you everyone for the given feedback and input !

Nicolas.

RCISFUN

My Feedback: (44)

Hello Nicolas;
This will be the last I can do on this for a few weeks, I just took a photo like yours, it appears that they must have made a correction on the second batch of Fomost's that Nitro Models received.

All indications point to a positive dihedral

RCISFUN

My Feedback: (44)

Instructor, your tank looks great, do you know what the volume will end up at?

As for Myself I will stick with the Du-Bro poly type tank, this tank was in my boomer that struck the ground..it didn't hurt it a bit, I think the fiberglass tank would have shattered.

Instructor

My Feedback: (16)

Hi RCISFUN,

When I was cleaning out the inside of the tank halves so the Hysol would stick, I added water to each side and then I poured the water into a measuering cup that held 32 oz. The measuering cup was full and then I poured it out and there was little watter left in the one half of the tank. I then poured that into the measuering cup and it read 12 oz. So with that reading, I think the tank holds 88 oz. Since I'm using a P-80, I wanted a little extra fuel. I now have to check it for leaks. To do this, I'll surmerge it in water and blow air into it, no bubbles, no leaks...

Larry

cairoman

So, based on all this, are we flying next week's Sunday or not????

Chris

SpiderJets

It is very good news to hear your wings are OK ! [8D]

Too bad however it still leaves us behind with the feeling of winning a lottery ticket if you happen to have a good set of wings... [&:]

Nicolas.

SpiderJets

Just closed the right wing too again, and tomorrow I will do the entire wing glassing.

Note that I did use for my first set the 'Z-Poxy Finishing Resin' and I could peel off the CF layer from the balsa very easily. Looks like this epoxy resin does not really penetrate into the balsa.
On my new set of wings, I'll use the 'R&G LF+LF1' epoxy resin, which is much more "liquid" and of aerospace certified quality grade.

Nicolas.

SpiderJets

Chris,

Definitely. Bring your video camera, I promise you a rolling circle at 20 Meters altitude.

Sandor,

Don't forget to send me the Jet A1 nose retract unit or he has to hand launch it !
PS. Most likely, I might be joining Christos on Tuesday the 15th to your place.


Nicolas.

SpiderJets

Great tank ; 88 oz is 2600 ml. Be careful with the extra weight, the Formost likes it light, you really feel it in flight.

digitech

My Feedback: (10)

retract is underway

anyway between 9-00 and 11 am i am at the dentist dont come to early.

digitech

My Feedback: (10)

i use some methanol for thining the zpoxy then it works ok , you are right from stock it is to thick.

RCISFUN

My Feedback: (44)

Ouch....Good Luck

digitech

My Feedback: (10)

i am used to it now , wnet allready 3 times in 2 months/
i had a real nice bycicle rack in there.
so this time its a walk in the park.

SpiderJets

For those not familiar with thinning epoxy resin : be careful, adding methanol works (use MAXIMUM 10%) but degrades the resin quality too as it hampers the chemical reaction between the two components. The resin does not cure to full hardness anymore and thus becomes in laminating more "elastic" instead of hard as glass. For most of our applications, it is nevertheless still completely OK. Best to do in such case is to do the first coat of resin in thinned form (this layer only has as purpose to penetrate the wood better and just tack the fiberglass cloth to the balsa skin), but the second coat (after full curing of the first coat) is to be done in unthinned state. Still surprised that most modelers always apply WAY TOO MUCH epoxy on the first coat, it must be as dry as possible and you must remove ALL possible epoxy resin of the first coat with kitchen paper before allowing to cure, until it looks like you have almost removed everything. I also use a foam paint roller of 5cm width as this applies far less epoxy than brushing and you can 'press' the epoxy in the wood.

Hope this was some useful side information.

Note that some manufacturers of epoxy resin (like R&G) have 'Active Thinners' for epoxy resin which are chemically better suited than methanol. But again, then it is better to select the right product anyway (like the LF+LF1) from the very start.

Nicolas.

SpiderJets

Hatch
---------

Use two Multiplex Hatch Latches instead of the hex bolts in the kit...


Glassed wings
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My wings are glassed now .... Not fully cured yet but... What a difference in strength ! [:@]

RCISFUN

My Feedback: (44)

Nicolas, remember you said you would stand on them, or did you mean stand behind them

SpiderJets

Rich, yes, I know what I said. [:@] I have the feeling I will have to keep my promise... [:@][:@][:@]

Nicolas.

RCISFUN

My Feedback: (44)

Sandor,
I received my struts today, very nice workmanship

Thanks again

Rich

RCISFUN

My Feedback: (44)

Warwick,
I added the formers you requested to the PDF file, I need to add the tray drawings, will do at the end of the week, hope this helps

[link]http://www.filecrunch.com/fileDownload.php?sub=359d4e1f511f192aad382c4863f31 317&fileId=136951[/link]