Jake Ruddy

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Hey guys

A couple of months ago I was asked to do a review on the ExtremeFlight Yak 74" ( http://extremeflightrc.com/html/74yak54.html ) and Brillelli 46cc gas engine ( http://www.brillelli.com/brillelli_010.htm ). The complete combo can be found at http://www.brillelli.com/brillelli_012.htm

This plane was actually already built and put together by aerobob, but unfortunately he could not complete the review and I was asked to complete it. The plane was disassembled and shipped to me. I have take a bunch of pics myself during engine mounting as well as radio gear install and teh fuel tank install. RCU and Mike East have been nice enough to allow me to use some of Mike's pics from his review of the EF 74" with an OS 1.60 so I can outline the build visually. Thanks guys!

The plane itself has been completed now for I would say 6 weeks.. it has made it to the field once so far and I discovered el. servo issues which turned out to be a flawed motor in one of the servos. Unfortunately the weather has not cooperated ever since and I havent had a chance to bring it to the field since. Hopefully I will get a break here and the weather will drop the winds down and bring out some sun for a change. In the meantime I thought I would start the thread and start sharing some pics of the review.


More often then not now adays with servo technology advancing you see a lot of people throwing 250+ oz servos in all their planes. Nothing like that is needed for a plane this size and in my opinion it's not really worth spending $500 or $600 in servos for a 74" plane. I am not saying the servos are not worth it.. but it's rare to see a review that is done with the "guy on a budget" in mind. Therefore I decided to use quality metal gear servos but not the top of the line digital servos.


Plane Equipment:

4 x Hitec 645MG for Al and El (133oz at 6v)
1 x Hitec 5645MG for Rudder (168oz at 6v)
1 x JR standard on Throttle

1 x NoBS 1400 6.0 for servos
1 x NoBS 1400 4.8 on ign

2 x Cermark DSC switches on radio and ign.

1 x Futaba 138 PCM reciever

16 oz standard tank with proper gas stopper

Brillelli 46cc gas engine
21 x 8 Zoar prop

All standard hardware is used on this plane


I will break down the build in the next posts with pics.... and soon as the weather works with me wil sharea few videos.




Enjoy!

Jake Ruddy

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When the day comes that your boxes are finally delivered you will see that Chris has taken a great deal of care to ensure your plane arrives. I don't have pics of unpacking the engine... but I can tell you Scott takes great care that your engine is packed properly as well...

Jake Ruddy

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You will quickly notice as you start to unpack your plane that there is lots of quality gear here!

CF wing tube
CF Stab tube
nice hardware package
robart hinges
removable stabs
snap on canopy ( no need for screws it's a spring loaded latch!)
etc etc.

Although I didn't unpack it myself orig. I have yet to hear of very much ironing going on... you will find the plane will arrive it amazing shape with little work to do outside of putting it together.

Jake Ruddy

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The plane comes with some very nice lightweight phenolic control horns. These are not only fairly easy to install, but they give you a strong, lightweight, control horn that looks and performs great! Your ball link goes in the middle for excellent control.

All of the slots for the horns are pre cut which makes install easy to do as well as makes sure your alignment is properly done to ensure proper performance.

The biggest thing here is that you want to make sure you remove the covering so that the horn can be glued directly to the surface for maximum strength. Although the slots are pre-cut you want to make sure that your pivot point (where the ball link bolt holes are located) is on the center of the hinge line. You will also want to compare the elevators to eachother to make sure they are as close to identical as possible, this will help make sure your elevator throws will be as easy as possible to match. If your horns don't match it will make it will make control throws extremely hard to match.

Once you have tested to make sure they align you can use 30 min epoxy to glue in the horns... make sure you double check them after you install them with the glue.

Jake Ruddy

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Next will be hinging your surfaces. This won't be too hard to do because the plane includes robart hinges and is pre drilled.

Personally I am a fan of gorilla glue for hinging. I used to use Epoxy, but Gorilla Glue gives you that added expanding effect for an extra peice of mind.

There are many techniques you can read about when hinging a surface, one I learned last year and works for me well consits of the following.


1. Make sure all hinge holes are clear of any loose materials in the holes - I usually just take a blade and clean them out.
2. Apply a small piece of blue painters tape about 1-2" long covering the hinge hole on the surface
3. Take an exacto blade and cut a circle uncovering the hole where the hinge point will go
4. Lightly tape your exacto blade and cut the painters tape in half centered over the hinge hole so that you can easily remove the tape later in 2 smaller pieces
5. Heat up some vaseline and dip the hinge in it or use a drop of oil so that glue can't stick to the metal pivot point
6. Take a tooth pick and grab as much Gorilla Glue as you can on the tooth pic and then put it in the hing hole covering the entire contact surface of the hole
7. Place hinge in (make sure it's straight!)
8. Repeat for every hinge of the surface
9. Every 15 mins or so you will notice some glue expanding out of the hinge hole.. just wipe it clean - after an hr it will stop

Now wait 2 hrs and then repeat the steps attaching the surface to the plane ie. Al to the wing

After 2 hrs or so you will be able to peel off the painters tape ( might need to use thatexacto blade again) and you will have a hinged wing.

Jake Ruddy

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When doing your hinges you want to keep the hing gap as small as possible. In order to get full 3D throws sometimes you need to leave a small gap to allow for full deflection.

It is EXTREMELY important for you to seal that gap. If you do not you are opening the door to possible flutter which can destroy a wing and / or plane in a matter of seconds.


To do this I use the same hinge tape you use on foamies. It sticks very well, is almost clear, and it doesnt make any noise like when you use covering like ultracoat. That snaping noise from covering always got to me

I just lay the wing or el. down and tape from the bottom.

1. Extend the surface deflection to full
2. Start with the tape at one end of the surface and stick it to only one surface
3, Slowly move to the end of the wing or el. with the tape trying to make sure it is only sticking to one side
4. Cut the tape to length and fold it in half towards you so that you can get the tape right down in the gap
5. Slowly work the tape across the entire gap making sure you have secured it properly on both surfaces
6. Trim any excess

Jake Ruddy

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Well let's look at the fuse and canopy - all of this is pretty straight forward... Gotta love the spring loaded Canopy release

Jake Ruddy

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Time to attach the stabs.

Very important here in any plane, but especially because this is a gas plane and will have more vibration make sure you use loctite on the stab screws.. Blue is fine.

krayzc-RCU

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sweet from the minute the package was delivered

x-craft

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I've got my Yak all ready to fly but am waiting for winter to leave since it came back and ruined our lives![]

This is my first ever Arf and I have to say that it's impressed me the whole way through. Excellent packing, no wrinkles and still has not wrinkled even after sitting out in the sun. Everything went together perfectly with no troubles at all. Good hardware included in the kit and I love those control horns, they seem to be very strong and I doubt one would ever fail. Canopy latch is awesome!

I got mine in all white so I could do my own color scheme however that red and white option looks great in my opinion. I just wanted something that didn't look like everybody elses.

With a surplus G-38 laying around I decided to mount that up. I have one in my TF Stinson and it's a great reliable engine. With plenty of power and that plane weighs a ton. I've had the Yak running with a 20x8 prop and that baby has a ton of pull. I'm guessing it will be off the ground in 20 ft if I really wanted it to be. My real goal is to have a good precise airplane to fly IMAC with. The extra weight of the 38 does not concern me at all due to this. At some point I may install a C&H ignition so I can shed the spring starter, magneto, flywheel etc. Dry weight is 13.5 lbs.

Overall, my opinion of this airplane is high and I have not flown it yet. I'll reserve my final judgement until then but for now I love it! EF really seems to know their stuff.

Jake Ruddy

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x-craft looks good... always nice to see a custom covering job on a plane.. I did teh same with my WH Cap

I will be adding some more pics etc a bit later tonight!

x-craft

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Thanks Sinergy, I'm happy with the way it turned out. In the picture there is no spinner or pants but I now have the pants mounted up and I'm going to pick up a tru turn spinner in Toledo this coming weekend. Can't wait for this snow to melt and field to clear off.

Jake Ruddy

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Alright well I didn't put my wheelpants on.. our field a little bit bumpy and unless it's 30% or larger I generally skip the wheel pants.

Many of you appreciate a completed model so I will share some pics of Mike East's install. The wheel pants are pretty straight forward, much like most models. They have a piece of ply which you must attach (use epoxy) to give added support for the wheel pant. There are several ways to attach the wheel pant but one of the most secure ways is to use 2/56 or 4/40 blind nuts .. I even use some blue loctite.. If they come loose they get destroyed in a hurry.

The landing gear uses 4 bolts to mount to the fuse through some aluminum angle bracket for added strength. Remember.. with platsic lock nuts you DO NOT want to use locite.. it weakens the nylon.

Also a small note to make would be to make sure you grind a flat spot for the wheel colars. If you have ever had to do a one wheel landing once or twice you will appreciate the extra 30 secs of grinding to avoid this happening to you. Recently I started using PSP axels because they are super light and have a nice e-clip so that you just snap it on and forget it. Although at $20.99 a pair you have to decide if it's worth it to you or not.

Jake Ruddy

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Next is the fuel tank mounting.... before we get into putting it into the plane I wanted to touch base on a couple things.

Many people don't realize that over time your fuel tubing will swell a bit and not fit as tight as it did in the beginning. This is often the cause of an unexpected deadstick... whether it be a line to the engine or more likely your clunk coming off. It is very important to spend the extra time to secure things properly... meet your new best friend, the zip tie.

You will notice that I zip tie every single line on the tank all the way through the fuel T, the filler line, vent line, and on the engine. A dead stick can be.. well deadly if it happens at the wrong time I went to home depot last summer and bought 1000 of the small 4" ties and 500 12" ties.. for the $40 or $60 I spent I won't have to worry about being in final install mode at 2am and not have a tie to secure things. Some times this leads to taking a chance because you really want to fly that modle the next day... NOT WORTH IT.

krayzc-RCU

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sinergy
i love that blue stuff to it stay so much softer...

Jake Ruddy

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The tailwheel is made of carbon fiber and is very light. It's a simple design and looks effective. Personally I have mixed opnions of whether or not the metal on metal design with cause any RF interference. Currently I am changing the design but I will show you some pics of how t's suppose to look. I will post my setup later.

Jake Ruddy

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The tank install has some options.. you can use the standard spot or do some modifications to move the tank back over the CG. In most cases if you have serious goals in regards to your flying you want to get that tank on the CG. It just makes for a smoother more controlled predicatable flight.

I opted to keep it simple and use the stock location. It's a simple mod to make it fit under the wing tube... if I find a noticeable difference then I will def. sped the time to move the tank under the wing tube.

For me I usually start off with KEs and rolling circle type flying and then as I get in the 2nd half of my flight I hack out some 3D As the fuel is used CG will move back which will be find for the end of my flight.

You will notice the vent line loops around the tank, this makes a trap so when you tilt your plane up with gas in it, it doesnt leak all over.

Make sure you put some foam under your tank

Jake Ruddy

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ya krayzc.. blue stuff is good

krayzc-RCU

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looks like you have made the cover over the motor box were u can get to it by adding a block to run screws down in. I would think the RF inference thing is blocked by a foam tire and the gear being made out of carbon fiber....

one other note how do u feel about felt clunks i run those on all the gasers as they'll work in filtering along with being heavy to suck up the fuel in a sponge fashion if u get down to the wire..

Jake Ruddy

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Engine mounting... well aerobob had already done this work for me so all I had to do was mount it.

However, I will let you know how I would have done it.


First you will want the cowl blocks in place, and have test mounted your cowl once.

Cowl
1. Epoxy plywood blocks in place
2. Drill the mounting holes for the cowl
3. Make sure you harden the holes with CA
4. If you have bonded washers then use those to mount the cowl (wont come loose with vibration)
5. Measure the distance from the firewall to where you want the spinner backplate

Mount engine to al. rails with the matching distance so spinner backplate will be where you want it.

Mark your thrust lines

Now we can mount the engine.
1. Grab a ladder and put the fuse upright with the rudder at the floor.
2. Then Taped the fuse to ladder so it would stand straight up by itself.
3. Set the engine on the firewall ( probably wont sit properly)
4. Put on the cowl so we can center the engine.
5. Try and tape or trace where the engine rails are going to go and where you need to drill
6. Drill holes after you have removed the cowl and engine.


Now just mount the cowl and engine to see if you are centered where you want it.


One thing to note here... make sure when mounting your engine you use fender washers in the back of the firewall and locwashers to make sure your engine stays mounted securely. You should check the tightness often.

Jake Ruddy

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Well I didn't do the mod to the engine box, that was aerobob's handy work. Generally I just mount everything outside of the box and zip tie it to the sides. In this case it was a nie clean install and the work was done, so why not use it I readded CA to the holes to mak sure the screws stay tight and they have nylon washers under them.

RF wont be a factor because it's metal on wood... but you dont want it coming off in flight

Felt clunks are nice to run on gasers... I just use a plain Jane one. I have an electric Jersey Modeler which has a filter inside and a nice inline filter that the gas goes through before it reaches my plane.

Jake Ruddy

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I will post some more tomorrow night....

krayzc-RCU

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yeah i have not mounted my motor yet but when i do i will use that bolt the top on part. My Dave Patrick uses the same idea but that came from DP himself....

Josey Wales

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Nice graphics!

krayzc-RCU

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JW,

u know the deal why re-invent the wheel when it rolls good as is lol u da man!