delateurj

Hi,

Been racing for awhile, starting with T-34, then warbirds, 424, ef1 and 426 so it was time to give a 422 a try.

Settled on the Sweet V and thought I would share my assembly experience, not because I am an expert but because I am not and will likely have run into things and have questions about things that other first time Q40'ers may as well.

I'll try to create a more detailed shopping list but you can get all the specialized items you need from the following vendors, all of whom have been very good to work with:

www.cmadracing.com

www.darrolcady.com

www.sam-rairacing.com/

aeroracingengines.com/

www.kirbysgraphics.com/

I went with a Nelson for the engine but people I have been learning from run Jett's as well.

Was too anxious to get it done so this thread is really in retrospective since its pretty much done.

Attached are the before and after pictures and I'll start posting the details.


Regards,
Joe DeLateur

delateurj

Started with installing elevator servos.

I have settled on Futaba 9650's for my 426 Ninja's so to keep fleet consistent I went with those as they seem to be one of the servos recommended for 422. I like the combination of digital for good centering and plastic gears for creating less slop over time than metal.

Bit longer than the JR 3121 or Hitect 225's or digital equivalent often used as well, so had to do a fair mount of trimming to fit into the pre-cut and installed servo tray for the Sweet V elevators.

Also are a bit higher from mounting lug to servo arm dimension so it was a little tight on the pushrods clearing fuse so I needed to relieve a little area. (Scratch marks on fuse were my doing, didn't come that way, when trial fitting wing first time make sure to slide leading edge in place into recess and then drop trailing edge or else the very strong/sharp trailing edge of wing will easily ding fuse )

Next time I might widen up the servo area a little more and put some space between the servos so the control arms are in the center, then pushrods will easily clear fuse.

delateurj

Elevator pushrods used carbon fiber rods. Nice write up at Darol's site.

Clean and scuff up portion of control rod to be inserted in CF rod.

I glued using IC 2000 (rubberized CA), others options are epoxy or jb weld.

I put the z-bend on the servo end prior to gluing into CF rod. Then with servos installed elevator clamped to neutral and control rod on arm, apply glue to rod, slide rod into CF tube and put arm on servo at neutral.

Note: I used the rods with 2-56 threads at the end (not all thread) and the 1/8" cf tubes that are a slip fit with these. However, I read that some use 5/32 cf tubes with brass couplers inserted for 422. Since this is dual elevator 1/8" should be fine.

Ball links are popped onto control horns through access hatch (keep an eye on that little round piece of plastic, managed to loose mine and probably got swept up without notice in one of my clean ups)

Note: There is some argument that the risk of ball links popping loose should be avoided by using clevis'. As you see later, I went with clevis for aileron but with the preinstalled elevator horns I actually could not screw on the necessary horns to use clevis because the two elevator links were too close to each other. Others are using ball links so I did not consider this a show stopper but thought worth mentioning.

delateurj

Mounting the elevator is pretty easy since its all pre dilled and tapped. One hole needed a little filing to line up with the hole in the fuse but it was minor.

delateurj

Next step I took was to cut out some of the wing section to allow a Jett 6 oz bubbleless tank (standard one, not the “slim” one) to sit back near the cg, level and near the same level as the spray bar of the engine. Staying with the width of the existing opening of the wing. Remove wing skin so the total opening extends to 3” inches back from the leading edge.

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delateurj

Next was mounting the landing gear block. Its marked which way goes forward. The landing gear go with straight edge forward.

The front edge of the mounting block is set 1 1/4" from leading edge.

Prepare the area for glueing the landing gear mount and aileron servo mount by sanding through the paint down to but not into the glass.

Drill some holes in the flange of the landing gear mount will help with adhesion.

I like to use West Marines systems epoxy and adhesive filler to do this type of work.

Mix it up with enough filler to make a paste almost toothepast consistency.

Spread liberally on mounting flange and on the inside of the sides to further strengthen (some have added ply doublers to the side).

When glueing use long straight edge to assure landing gear will be parallel to leading edge of wing and measure to make sure centered in wing.

Drill and tap for 1/4-20 bolts.

(By the way, the picture showing the straight edge to check on alignment with leading edge has one of my sillier mistakes in it.....can you spot it....will be revealed in next sentence)

I put a hole in the wing for the aileron servo lead but of course this wing sits with the servo on the bottom side of wing away from the inside of the fuse so hole is wrong side....oooops....)

delateurj

Glue in provided aileron servo mount and cut out to fit servo (I used 9650 for aileron as well).

Screw in provided bolts and cut to desired height. I went with 1/2" from top of wing skin which in retrospect was shorter than I would like (and there is room to go longer.)as I am only using about a 1/3 of the servo throw as a result.

Screw in all the way and then back out a turn or two so you are not interferring with the wing skin on other side.

I glued them in using rubberized CA. This seems to have worked well on the ninja.

delateurj

Time to do the motor mount and fuel cut off and other plumbing.

Needed to grind away a little of the epoxy ridge where the needle valve assembly is for the motor mount to sit flush (Jett Motor Mount with integrated remote needle. Plane comes with firewall drilled for this with blind nuts installed (well one thing that builder missed was putting in blind nuts but that just took a few minutes to do)).

I use the Sullivan 3/32 which is a popular choice. Large enough for necessary flow but small/flexible enough for easy fuel cutoff.

Lots of fuel cutoff threads and way to skin this cat.

I went with a the basic "U" approach using .048 music wire.

Initially went with 85mg which worked okay. Servo having only two mounting screws lead to a lot of twisting so pulled it out and stepped up to a 225mg and that handles well.

Setting up cutoff so that the servo arm is in the position shown when in cutoff position minimizes stress on the servo.

Note that the first picture showing the mount and the plumbing has the feed line from tank coming throught the firewall. Seemed all nice and clean and I wondered why others routed in more convoluted way until later I realized I would not be able to refuel without removing the cowl or cutting a pretty big hole in the cowl so I could pull the line out to refuel.

Last pictures show final routing using a 90 degree fitting.

delateurj

Okay rest of engine area stuff.

Kit provides a phenolic piece that bolts to the front of the motor mount and then is epoxied to the front of the fuselage to "tie" the front part of the mount to the fuse to make mounting more ridgid. Any energy wasted in the engine moving around is energy not going into making the plane go faster (first thing Mick Crawley who first help me in T-34 racing taught me about importance of rigidity of mounting and fuse. Debateable if this is noticeable but easy enough to do. Had to file holes a little to fit. Used West Marines with filler again but went with faster hardener as weather was a little on the cool side.

(Funny note, my first question to Tom Scott at cmadracing who has been very patient and helpful was "What is this phenolic bulkhead for and where in the fuse should I glue it". He then explained how it was to be used to tie down the motor mount to the front of fuse)

Open up the hole in the cowl so it will just fit over the venturi.

Cowl ( and belly pan ) are held in place with tape. What is everyone's favorite tape to use for that by the way?

Trim so cowl will not interfere with muffler.

I wondered whether I should trim cowl to expose more horizontal fins but feedback I have gotten so far is that is not necessary for necessary cooling.

You can see that the plane is nicely set up to give a nice small gap between spinner and fuse/cowl and matches the 2" inch spinner when using the Jett motor mount with needle which I think is a little longer than other mounts.

delateurj

Lets see....what's left.

I used a 500 mah LiFe battery by ProTek. Been using these in all my race planes last few seasons and very happen with them. I cycle them about 15 times before first use as recommended on the A-Main hobbies site where I buy them. My ninja's typically use about 30 mah per flight. Did some banging of the stick constantly with throttle on shut off for 5 minutes and used about 45 mah so feel comfortable there is plenty of margin.

Battery tucked nicely into area by one of the servos. You can get an idea where it is in the picture showing me cycling it in the plane.

JR 921 Rx may be a little on the big/heavy side but finished ready to fuel I am only 63.2 oz. Does not include wheel pants and I still need to add a little lead tape to get it at starting cg of 2 1/16" from leading edge.

921 also means I can get 11ms response instead of 22ms with Rx like AR7010. If there is anytime I will notice the difference it will be in this. 200 mph means 3 feet covered in 10 ms.

Also the AR7xxx I had in there gave me no throttle response once for no reason I could figure out and with something like this, if in doubt, its coming out and I had a 921 that's been trouble free but was not in use.

A little lead tape on port wing underside wing tip to help with lateral balance. Guessing it will need more but will trim following methods described at Dubb's site.

Oh yeah, add the nice graphics from Kirby's Custom graphics. He has Ninja and Sweet V loaded into his design software and many existing designs. This is a variant of I think a Randy Smith design.

I've used him for my IMAC stuff as well. Great to work with. Use Rapid Tac liberally and squeegee patiently and turn out pretty well except where the leading edge wing yellow section was long enough and there is just enough of a compound curve that I didn't do as nice a job getting that to be smooth as I would of liked and ended redoing some of the outer part of the panel.

delateurj

Next steps:

Break in engine per instructions at aero engines site. (Many threads on this).

Take her out to crows when weather good stay on the right rudder on take off and trim her out and start flying the course after warming up the thumbs with a few 426 flights.

Oh still need to put on wheel pants at some point.

If all goes well, see you at the Basin.

- Joe.

PylonDave

Enjoyed the build Joe!! Get her trimmed and see you at the Basin.

sahartman21

Just a comment for the tank location should someone want to run the Jett LS in the model. Initially try a higher tank installation (such as on the top of the wing). The Jett seems to prefer a high tank installation.

Thanks for taking the time to show the assembly of a very popular model!

Scott Hartman

Randy Smith

Tank position with the LS motors tends to be a factor in getting a good needle setting.
I run the Nelson LS in my Sweet-V and I like to run the Jett flat tank. I install it 'high' in the fuselage. ie. I put it under the front wing hold down blocks.
A little Dremel work on the epoxy under and around the blocks and the flat tank slides in nicely under the two blocks. This is as 'high' as the tank will go.

This position allows me to set the needle very near peak on the ground. The motor goes just slightly rich in the high G corners and peaks on the straight away.

I have had good success running my Sweet-V this way.


Randy

SSAN

It also help with getting to pylon 1 much faster with the near peak needle setting on the ground.

MFLOOD3800

My Feedback: (51)

Joe,

Looking forward toseeing this at the Basin. I just sent my entry in and got my Proud Birds off the shelf.

I have batteries to cycle and one new motor to break in.

Let us knowhowthe testing goes!!