ToxicT
great work! one of the best profie EuFis that I have seen!
I believe CG should be around the spot where it says "29 inches" on pic in post 21.
We already had this discussion a while back on anoher EuFi project. Just do a search (CG Eurofighter) ...I believe it was over in the Pusher-Jets Forum.

canard is not different to convetional planes regarding CG.
Move "best glide CG" from glide test a few cm more forward and it sould fly fine.
whatch aileron rates. mine was very twitchy in roll.

good luck,
chara

Thanks Chara, I got a great glide CG right at that point so you were spot on! Thanks for the advice.

OK, got to thinking about this some today and something concerns me. The intake area is pretty generous but at the aft the opening for airflow is compressed. I suspect this is going to be a drag generator as it is so I am thinking of cutting some opening slots on the bottom deck to help reduce this drag. Any suggestions or ideas?

Thank You Chris, I missed those the first time through.
I may take a shot at the canards on mine,I like your thought on mixing them in after getting the model trimed out,should be a blast.
I am just finishing up a Shuman T-38 with a full flying stab and will use His settup for the canards.

Have you tried the gws hd props on your 2409....they make a cool sound at over half throttle with a good batt pak and in a high speed dive.
I know they are not as efficent as the apc props,but the growl is a riot on strafing runs and split S's on unsuspecting "targets"
Thanks for sharing your gift !
Mike

I believe that noise comes from the blades flexing under the load and excess speed they cannot take, which is not good.
Sooner or later it will fail and that could end with the demise of the model or even worse.

Del

Yes Del: I am sure the sound is from blade flex,the GWS Hd props have a different blade shape but also are more flexable than the APC ..that works out well if you are landing in rough terrain or have a model that is prone to prop strikes.
We do have a lot of time on these props with pusher jets and ww-2 warbirds
without a problem,but yours is a good point to remember.
As we start to push more power into lighter airframes it is very important to inspect our aircraft and to be alert to any unusual sounds or changes in flight characteristics.
Mike

Originally Posted by ToxicToast

Thanks Chara, I got a great glide CG right at that point so you were spot on! Thanks for the advice.

OK, got to thinking about this some today and something concerns me. The intake area is pretty generous but at the aft the opening for airflow is compressed. I suspect this is going to be a drag generator as it is so I am thinking of cutting some opening slots on the bottom deck to help reduce this drag. Any suggestions or ideas?

Tox you're welcome.
I wouldn't bother too much about the drag from the intake. your prime challenge will be to balance this model out CG wise without using lead. It will need lots of weight in front to place the CG at the sweet spot.
the intake is a perfect place to hide your battery etc inside and get nice clean lines. So no air will flow inside the fuselage anyway.
keep posting!

Torque roll
I built a FFF EuroFighter with the first set of plans.
I did it with a single fuselage section and the “box” on the bottom.
I used a “little blue” motor 2712-12 Outrunner with an 9”prop

The issue I am having is the Torque roll. I have 3 flights on it and they were all short. It wants to roll.
I have trimmed the roll out of it for launch. But do not have a long enough flight to see how it does at speed. This is the first small jet I have built with a large prop.

Long story short. (to late)
Will it want to roll “at speed”?
Will it want to roll at different speeds? (On and off throttle)

I have 3 other FFF jets all with big KV (2500) motors and small props 6”
They don’t torque roll, but I want to use the light “little blue” motor. It’s not fast but it has a ton of thrust.

13 dollar for a stickmount, firewallmount and a prop adapter?
That seems quite a markup to me. They are 12$ at Unitedhobbies.com...
(please do not start that 'buy from americans' flamewar again. please?)

Originally Posted by chara

...... your prime challenge will be to balance this model out CG wise without using lead. It will need lots of weight in front to place the CG at the sweet spot.
the intake is a perfect place to hide your battery etc inside and get nice clean lines. So no air will flow inside the fuselage anyway.
keep posting!

I had to use a 3s750 way up in front of the intake to get it to balance. if I use a 1350 pack I had to put it just inside the intake.

this is another reason I wanted to use a lite motor.

I would reduce the prop diameter,try 8 or 7 inch.

i have a Blu Albacorde with the Blue motor from United hobbies that i will use a 7X6 on. Not flown yet due to weather.

I have another one of those on a small ME109 using 8X6 no torque roll on that but it does have longer wings 28 inch. i launch at full throttle with an underhand lob.

I have Toxic's F14 with a 200w motor and 6X5.5 inch prop, again 3/4 throttle and let go vertical with no noticable torque.

Del

Gundy,
holy cow 9" prop is quite a lot of a prop! once you pick up speed and the surfaces become more effective, the torque roll tendecy will decrease. But I guess your 9" prop will not deliverr a lot of speed anyway. Those are made for 3D planes in tractor configuration.
The EuFi (like all jets) looks best in the air when flown fast I would recommend a smaller diameter prop with lots of pitch. The GWS 7x6 works pretty nice on foamies. Or maybe a Günther 5x4.5 for higher kV motors.
Good luck with your next flight!

OK, decided to go with working canards tied to the flaps switch. When I toggle the switch, canards go active and mix with elevons. That way, I can hopefully get the fighter nice and high before I start experimenting with the canards.

Now, finding the CG on this bad boy out meant three options:

• 1. Adding lead to the nose so that I can keep the battery around the intakes. Wasted weight and unsightly but effective.
  2. Keep the TP Prolite 1320 intended originally for it in a cut out way up front by the edge of the canopy. With the TP1320, AUW was about 12oz. Nice weight, but trying to get the battery farther back.
  3. Get a new battery with quite a bit more weight and tuck it in the intake. Not ideal but better than just relying on usless weight like lead.

I ended up going to a LHS and got some opinions on this. Decided to pick up a XUS 2130 20c for only 50$, a great deal and certainly useful in future planes since this is now the largest battery I own. Its heavy, but fits nicely in the intake. If it dosent work out, I can always cut the slot up in the nose for a 1320. Hopefully the 2409-12 with a 7x7 prop can keep push it fast enough (220W at WOT/22A). If my LHS sold a little screamer jet park version, I would have picked it up instead.




So now I have a hefty 1lb plane with working canards. Not exactly as I started out with in terms of goals but I'm hoping the maiden will be a success.

-Chris.

Posted a quick video (divx format) of the canard test here:

https://www.rcgroups.com/forums/show...45#post6935500

Did I do the direction right? Throws too extreme?

Watched vid, they work in correct sense as far as i know, its only like mixing in aileron as flap for extreme 3D.

Looking at pics 4 and 5, i would move the Batt to ESC lead to the left nacelle, keeps it away from canard servo/linkage and a little space to the reciever.

plane looks great by the way, any paint/tape for orientation being added.

Del

Looking great! nice and clean design, I love it! will look absolutely perfect with a touch of colour.

Throws are ok I would say.
Those pointy depron noses are VERY fragile. please be carefully on the maiden-would be a shame to brake it. ...or you could glue a CF spar along the forward half of the fuse/nose (along the corner where the vertical and horizontal parts meet) . Since I used this technique I hardly ever had a destroyed nose.
good luck