[fly_away]

I am building a plane for the first time. So far so good. Fixing the landing gear on this one was tricky but that is all done.

I had a question about the mounting of the motor and hoping someone can offer some advice. I have screwed the mounting bracket on the back of the motor and the mount to the square wooden piece. Do I:
a) Stick the wooden pc to the fuselage? OR
b) Find longer screws and screw them through the wooden pc and fuselage

TIA

[Skidz]

probably both.

[smuzz]

I wouldn't expect putting screws into foam to do any good at all.
You'd be better off drilling some holes (say 8mm or more in diameter) back into the fuselage about 30mm or so and gluing some wooden dowls or pegs down into the holes using plenty of adhesive. Then put screws through your ply mounting plate and into the ends of the dowls. It doesn't look like a very substantial plane, so perhaps two dowls would do it. Plenty of glue on the back of the ply plate would obviously a good idea too of course.

[Skidz]

Looks similar to Claudius's Extra 3D.

[fly_away]

I wouldn't expect putting screws into foam to do any good at all.
You'd be better off drilling some holes (say 8mm or more in diameter) back into the fuselage about 30mm or so and gluing some wooden dowls or pegs down into the holes using plenty of adhesive. Then put screws through your ply mounting plate and into the ends of the dowls. It doesn't look like a very substantial plane, so perhaps two dowls would do it. Plenty of glue on the back of the ply plate would obviously a good idea too of course.

Actually behind the foam is the solid fuselage. Machine bolts with nuts would be ideal but I dont think I can access the back of the firewall. I am thinking of stripping the foam from the firewall and glueing a block of wood. I can then screw the mounting bracket to this block. Yes it is very cheaply built.

Interestingly I heard from someone that engines in commercial jets are simply stuck to the wings by araldite and meant to break off!

[Claudius]

a) Stick the wooden pc to the fuselage? OR

This.

If I recall correctly, that's all I did with mine. Just used epoxy to join the wooden firewall to the front of the fuse (the foam will absorb the epoxy, forming a strong bond).

[robair]

G'day Sujit

I can assure you that commercial aircraft turbines are not merely araldited on.
2 pretty serious bolts do the job on an A320.
The thought of an engine breaking away completely quite frankly would be up there amongst my worst nightmares.
Oddly enough this event has occurred. From memory a 747 freighter threw an engine due to corroded mounting bolts, the engine then smashed the crap out of the adjacent engine + did substantial airframe damage. The flight terminated in a block of flats. Happened in Amsterdam I think.
I will edit this post later with a link to the accident report.
Truly scary stuff.
BTW good luck with the motor mount, looks like good advice has been provided for you.

Cheers
Rob B

[ConcreteTurtle]

I can attest that the fuse bolts that hold the engines to the pylons on most airliners are pretty epic. Funnily enough, they are called fuse bolts because they are intended to shear in case of a crash or striking an obstacle, better to lose an engine completely than have it damage the wing and fuel tanks inside I guess. Still, wouldn't like to be the guy who has to tell CASA about that incident

Sorry to take it off topic, look forward to seeing your extra down the field one day.

[fly_away]

I can attest that the fuse bolts that hold the engines to the pylons on most airliners are pretty epic. Funnily enough, they are called fuse bolts because they are intended to shear in case of a crash or striking an obstacle, better to lose an engine completely than have it damage the wing and fuel tanks inside I guess. Still, wouldn't like to be the guy who has to tell CASA about that incident

Sorry to take it off topic, look forward to seeing your extra down the field one day.

Here is some more authentic discussion on the issues involved:

http://www.airliners.net/aviation-forums...835/#menu1

Important points -
The use of shear bolts so the engine can simply breakaway in case of extreme vibrations.
The expansion and contraction of the engine.

But considering that epoxys are good adhesives but very poor with shear force I still think what this person was telling me may be legitimate.

Thanks for the invitation to the field and I look forward to it. Thanks Claudius for confirming that simply sticking it works!

[smuzz]

... Yes it is very cheaply built.

To clarify - when I said that it wasn't very substantial I wasn't suggesting that it was "cheap" in any derogatory sense, just that it didn't seem to be a weighty airframe and so as a result, there wouldn't be huge loads applied to the firewall in flight.
Anyway, if Claudio says glue will do it, then glue will do it.
Good luck with the maiden!

[fly_away]

... Yes it is very cheaply built.

To clarify - when I said that it wasn't very substantial I wasn't suggesting that it was "cheap" in any derogatory sense,

No offense taken or inferred. In fact I enjoy assembling these planes it is a challenge and I have learned so much already.

History:
I started on this a year ago and just could not get time to order the required parts from HK. Last month missus threatened to throw it out hence this scramble..

Anyway it is getting closer now. The Prop is fitted and the motor screwed and epoxied. Now the servos and I am done.

:-)

[Claudius]

Anyway it is getting closer now. The Prop is fitted and the motor screwed and epoxied. Now the servos and I am done.

Good to hear.

BTW, if you haven't done much flying before, it might actually be worth giving it to the missus to hold on to for a while... and getting a trainer in the mean time.

I've found it a very fun aircraft to fly, but definitely not a beginner's plane.

[secant0give]

Anyway it is getting closer now. The Prop is fitted and the motor screwed and epoxied. Now the servos and I am done.

Good to hear.

BTW, if you haven't done much flying before, it might actually be worth giving it to the missus to hold on to for a while... and getting a trainer in the mean time.

I've found it a very fun aircraft to fly, but definitely not a beginner's plane.

Get some cheep stick time on the sim and you'll find it's not hard to fly but you'll have to fly it. It won't fly it self like a stable trainer! But they doe fly nice and slow which is great!!

You've gotta love this kind of plane.
I reckon I've learnt more form flying my 3D foamy than any other model.

[fly_away]

Get some cheep stick time on the sim and you'll find it's not hard to fly but you'll have to fly it. It won't fly it self like a stable trainer! But they doe fly nice and slow which is great!!

You've gotta love this kind of plane.
I reckon I've learnt more form flying my 3D foamy than any other model.

I have crashed an electrafun xp a couple of times - and eventually lost it. Just flew away in high winds (oops - dont know where it landed!). I just could not get enough rudder control to bring it back. Anyway I fly my micro Parkzone Vapor in reasonable winds and I am quite good at it. Yes this is a super slow plane but very relaxing to fly. Somehow I am still timid with my flying and dont like the plane to get away too far from sight. I think I love Micros. Lets see how I go with this one.

[fly_away]

OK finally got this up in the air. I am using 10 x 4.7 slow props. Good News - This thing really takes off and I did fly it for a minute or so. Bad News - I broke 2 props.

I was looking for a folding prop of this size - tried HK and ebay no luck. Any tips on where I can find one?

[helijeli]

I've had this plane for about a year - actually took it for a fly in the local park this afternoon. I also just epoxied the firewall on. I've had a few minor crashes & it's pretty sturdy due to it's light weight and slow speed. Just a few cracks etc requiring a bit more epoxy to fix it. Mine only has a Towerpro 180W Bell motor which moves it along but not enough power for hovering & certainly not enough to pull out of a hover & go vertical. I've bought a 340W 2836 Turnigy 1200KV motor which should give it the 3D performance that will make it a lot more fun. Just have to work out how to mount it - need to reverse the shaft but not sure if that's possible. I also agree with Claudio that its not a beginner's plane - it rolls very quickly & you do have to actively fly it - the rudder certainly makes it yaw & you can simply make flat turns with the rudder alone. But it isn't that dfficult either and definately teaches you to use all your controls including rudder. If your breaking props, just use a prop saver which means the rubber band allows the prop to shift rather than break on impact. I think I've broken one prop since using mine on the Extra & haven't bent a motor shaft since - which was always happening when the prop was bolted on.

[secant0give]

You can always use a prop saver that will let the prop fold off to one side and not break when it hits the ground

[fly_away]

You can always use a prop saver that will let the prop fold off to one side and not break when it hits the ground

Ok thanks - I looked up Google Images and can see how a prop saver works. I was only thinking in terms of folding props. Thanks for the tip.

I think I will turn down the throttle to 20% till I can get a hang of the controls. My ailerons, rudder and elev are already at 40%. BTW I am using a 2200 KV motor and 3s 1500 Mah Battery.

The CG is very deceptive (10 cm behind the leading edge). It does not seem to have a range - a few mm back or forth makes it tip easily. So I am keeping the nose up a bit so hopefully in flight it shifts back. Not sure if that is the right think to do.

Is the cg for this kind of plane that important as compared to a glider?

[secant0give]

I set up my C of G for that kind of model so that once trimmed It will fly right side up and up side down level, with out loosing height or needing elevator input on about 3/4 to full throttle. ie once it's trimmed level right side up roll it over up side down and if it needs down elevator to keep it level then shift the c of G back a little. I do it in small steps over a few flights.

[gbanger]

Thats a great tip Jason......
All you novice 3D pilots take note.
This is the best way to tune you aircraft for well balanced 3D flight.

[fly_away]

I set up my C of G for that kind of model so that once trimmed It will fly right side up and up side down level, with out loosing height or needing elevator input on about 3/4 to full throttle. ie once it's trimmed level right side up roll it over up side down and if it needs down elevator to keep it level then shift the c of G back a little. I do it in small steps over a few flights.

Thanks great tip that one! Full throttle it wants to go vertical so perhaps with the 2200 KV motor I have will try 1/2 throttle.

I need to fly it level first before i can 3D..

Give it a go tomorrow. Still waiting for my prop saver. You are right about it has to be flown - I have been spoilt silly by my easystar which is a hard plane to bring down.

Time to join the club...

[Flying fisho]

Resurrecting a post from a few months ago because, as I have discussed with a few, I am keen to learn 3D flying in the sky & not just on Phoenix. Have been looking on HK, waiting for the Extra 300 s to come off back order and noticed this one which is available.
http://www.hobbyking.com/hobbyking/store...oduct=7368 .
Unless I am mistaken it appears to be a clone of the Extra 300S http://www.hobbyking.com/hobbyking/store...oduct=7372 .
Given that Claudio is so happy with his, I am wondering if I should just wait for it to come back in stock.

[gbanger]

What wrong with the Eratix Champ?

[secant0give]

You could always get one from SRL. they are a lovely 3D plane to lean on
Lighter and a little larger than the HK model. And only $30 fort he airframe
Absolute bargain !!

Here's mine flying late in the evening when the air is still

http://www.youtube.com/watch?v=SEWqpa17GdI

[Flying fisho]

Nothing wrong with the eratix, just wanting something cheaper to practice the 3D before pushing the Eratix beyond aerobatics.
Was talking to SRL at Hurstville indoor flying last thursday & he was quoting considerably more money than that & expressed it "takes a lot of assembly" indicating complexity. It also looked more fragile than the extra & I feel I will need it's "unbreakable" claim to fame.

[samste]

Nothing wrong with the eratix, just wanting something cheaper to practice the 3D before pushing the Eratix beyond aerobatics.
Was talking to SRL at Hurstville indoor flying last thursday & he was quoting considerably more money than that & expressed it "takes a lot of assembly" indicating complexity. It also looked more fragile than the extra & I feel I will need it's "unbreakable" claim to fame.

They look the same to me, Wayne.

And yes , i have Extra 300s one and they are lots of fun without the worry of expense when crashing, as they are very tough.


Steve

[Flying fisho]

Thanks Steve, can anybody recommend a power setup for me, HK suggest 1000 - 1200 kv, many on HK of varying diameter & length, not sure what will fit. I know turnigy plush speedies to be reliable, but all plush speedies between 18amps (too few?) & 40amps (too heavy?) on back order. Have Corona 929mg micro servo's at home, 2.2kg thrust is overkill but appear light enough.

[samste]

I had a motor from ages ago 1100kv using 10x4.7 prop 16 amps max
Here is the link That Claudio pass on to me with the motor he is running that works well.
http://www.hobbyking.com/hobbyking/store...oduct=5687

Steve

[Flying fisho]

Crikeys, all goodies on back order
http://www.hobbyking.com/hobbyking/store...Motor.html seems comparable but nearly adds 10% total plane weight

[secant0give]

Nothing wrong with the eratix, just wanting something cheaper to practice the 3D before pushing the Eratix beyond aerobatics.
Was talking to SRL at Hurstville indoor flying last thursday & he was quoting considerably more money than that & expressed it "takes a lot of assembly" indicating complexity. It also looked more fragile than the extra & I feel I will need it's "unbreakable" claim to fame.

I think you and SRL might have been talking about the Index which is the model he flies indoors?? That one is more expencive. It's got a lot more machining and yes it is very very light and does require a bit of fiddly putting together. Certainly worth it tho' when you see how they fly.
The Extra 330 that he makes like the one I fly is a lot easier to put together and is quite a bit more robust and a lot less expencive. Wingtipper also has one. They are very easy to repair and a bit stiffer than the EPP models.