mrenz66

I hope this post will help out anyone interested in building or in the process of building the Seagull Models 90 Yak 54. To start with I was looking to get into gas and this model coupled with the Zenohe20ei seemed like a good combo. Building the ARF was simple up to point of mounting the engine. I could not find any info on templates nor if any degrees of thrust right or down maybe needed so I mounted the engine dead center on the box, drilled the holes for the blind nuts. I made homemade standoffs using threaded nylon spacer cut 3/4� which brought the engine to correct specified length. After the electronics, batteries, receiver, and servos were installed I was ready to check the CG. Horizon has a bulletin posted that the correct CG is measured at the fuze not the wing tips. 70 to 80cm back from the LE. My Cg fell at 95cm from the LE and a bit forward of the spar. Before I get to “how did it fly� I will list my setup.

2700Mah nimh 4cell 4.8v pack installed on top of the motor box for ignition.
2700Mah nimh 5cell 6v pack installed in the space under the tank for the receiver.
MPI heavy duty switch for the ignition.
JR deluxe switch for the receiver.
2 JR 821 servos, one on rudder one on throttle.
4 Spectrum 821 servos to cover ailerons and elevator.
Hobbico heavy duty extensions 2 12� 4 6� and one Y
Weight 10lbs
Klotz R-50 mixed 32:1
Prop: Zinger 15 by 8

Sport throws and for its maiden flight.

elevator 3/4� U/D 50% expo
rudder 2 1/2� R/L 60% expo
ailerons 5/8 U/D 45% expo

elevator servos on mix 6 program (DX7) and AUX 2

How did it fly? Just great! I gave it a good run on take off eased back on the stick and it climbed out medium angle. The suggested sport throws coupled with my “ ton o expo� gave me a very docile plane. Just a little trim was needed for hands off. Landing took me some time. 1st try was a “bounce and go� 2 and 3 overshoot 4th try nailed it. I give the Zenoha 8 out of 10 for powering this plane. Good power to weight. I tuned the Zenoha a day before its maiden flight and found the factory setting ( a bit on the rich side) to be the best until the motor is seasoned then at that point I will fine tune the needles.

Hope this post helps others
Thanks for reading
Mike
secretary
Tri-County Wingsnappers
www.tcws.org

TimBle

what did you think of the overall quality of the ARF?

is the covering Oracover, any problems here.

how about the joints in the woodwork?

WCB

Be careful with the paper thin sheeting on the wings. I'm flying mine with an SPE26 and Xoar 16x6. Good combo.

mrenz66

Its built on the light side. The sheeting on the wings are delicate so handle with care. All glue joints seem solid. I am not sure if its Oracover....I guess whatever Horizon/Hanger 9 likes to use.....Ultracote? Overall quality is good.

Mike

mrenz66

I found that out quick when handling the wings. The SPE26 is my next engine which will go in a CMP Giles 202 140 version 1 or option 2 is the E flite power 110

Mike

WCB

My SPE26 runs great but is definitely not a powerhouse. It's fairly lightweight so the power to weight ratio is decent. It turns the Xoar 16x6 at 8400 rpm.

TimBle

ah it seems most of these erobatic planesuse thing sheting on the wings. I've had to CA the cracks in my Extra already and that was just from carrying it to the flight line!!

WCB

It is the price we pay for having lightweight airplanes.

mrenz66

If I get someone to help me out holding the plane I tell them to be very gentle.

RCVFR

My Feedback: (7)

The high stress points designed into model planes are around the engine mount and landing gear. I carry my planes with one hand one the prop or spinner and the other on the landing gear. Usually, the wings are not strong enough to be used as handles.

WCB

True that is a good practice, but at some point you are going to have to handle the wings to either put them on or take them off. That is where I broke the sheeting on mine. It is paper thin. Just look at it hard and it cracks. I am being serious.

wcb

RCVFR

My Feedback: (7)

WCB, I don't doubt you at all. I have been flying mine for over a year, and I know there are some places on the plane I would like to see heavier wood - such as the bottom section just behind the firewall. After a year's worth of riding in the cradle to and from the field, I have had to rebuild that section, as it crushed just from the weight of the engine (26cc gasser). But, it is what it is, I guess. I do like this plane.

WCB

Jim,
I had to rebuild that same area on mine..bottom right behind the firewall. I just set it in a padded cradle and heard "CRUNCH." You're right.."it is what it is." Very nice flying plane and inexpensive...but very delicate.
The plane must be pretty tough though. I done an outside loop with a violent snap roll pulling negative G's and broke the pilot loose

Bill

mrenz66

I carry mine by the landing gear. I do not even want to hold those wings. I have also noticed that the covering wrinkles when left in the sun....second I am going to have to shrink it. All said.....it flys great.

Mike

LSP972

My Feedback: (13)

I bought one of these on impulse two weeks ago. After looking at it in the LHS, I was quite impressed with the build quality, fit, and finish.

I got started on it, then dropped it to get my H9 Extra 260 resurrected. That's done, so I'll get back on this Yak straight away.

I'm putting a Laser 150 in it. Should be near perfect for sport aerobatics....

.

mrenz66

The VP from my club has a older one which inspired me to pick one up. My setup is a clone to his except for RX pack placement. The Yak excels at sport aerobatics and is probally the best out of my fleet.

Mike

DirtTorpedo

I have one of the older blue and yellow planes...

I have an os 1.20 in it swinging a 14X7 three blade prop and the performance is.. impressive!!!!!!!!

I've noted only one bad point about my plane... it tip stalls like a MUTHA if you give it too much elevator to fast!!!! (did that with any prop)

I've got a 2400 Mah pack in it, a Spectrum AR-6200 and a set of JR servos and i feel its still a bit chunky...

Maybe they changed the build of the plane because my wings are solid... the wing sheeting has never given me any problems..

Another point that, while not necessarily bad.. is that its FAT.. I bet I could shave 1/2 a pound or more off of it by changing out some parts and a few other mods. Carbon landing gear alone would do wonders!

LSP972

My Feedback: (13)

Any of you guys have trouble with the cowl screws eventually getting loose?

I mounted mine today, and used the four pre-selected points (and what a PITA having to reverse-engineer the way I usually mount a cowl!).

Anyway, I noticed that the screws don't have a hard point; IOW, they're going into medium-hard balsa. Wish I would have snapped to that right off. But I'm going to add a few more attachment points, using hardwood and 2-56 bolts and T-nuts.

I also found a carbon fiber gear that I had purchased for another model but never used. Its too wide, but the height is exactly the same as the kit gear. So I'll just saw that puppy in half, trim to fit, drill two extra holes, fair the struts in with some scrap, and voila.

What's the consensus on the kit-supplied tail wheel unit? It looks okay, but I'm thinking about an OMP Haigh unit. Got one of those on my H9 Extra 260, and it has been totally bullet-proof.

.

WCB

I had to do the same thing.

I haven't had any problems with that.

Bill

mrenz66

I installed ( epoxyed) the Du Bro threaded inserts and used cap screws......there is a SMALL strip of ply I noticed but you have to hit it dead center I missed the mark on one and drilled into the soft balsa so to reenforce the insert I used some toothpicks around the insert.

Mike

LSP972

My Feedback: (13)

Man... getting those T-nuts in place was a MAJOR pain in the kiester. If I had followed my original inclination and put two per side relatively close to the mid-line, it would have been a snap. But, nooooo... I had to get them more offset for symmetry, and was working up in those near-inaccessible corners just behind the firewall, outboard of the motor box pieces.

But its done now; finishing up the cowl/front end can proceed. The rest of the model is straight forward... I just need to squeeze some time to work on it.

.

RBSteffey123

My Feedback: (57)

I am having the same issue with cowl screws coming loose and having to use larger screws because the balsa is so soft.  Would filling the holes with tooth pick and CA ?  I was also thinking of installing some blind nuts or  threaded insert?

RBSteffey123

My Feedback: (57)

Seagull Yak 54 90 size.  Mine is setup with a Saito 120 swinging a 16x6 about 9,500 rpm full throttle.  Engine has about 1 gallon through it, fairly new.

mrenz66

As with most glow engines take them apart and clean them on your down time. Replace seals/gaskets aswell.

Mike

BoiseBee

My Feedback: (3)

Hi Mike,
Thanks for the info and pix. I went gaga over this bird the first time I saw it. I was still in the process of deciding whether I wanted to get it when I was offered a low time OS 160 and bisson pitts muffler at a price I couldn't refuse. So now I'm committed (or maybe should be? ). If you don't mind I'd like to ask a few questions:

What is the weight of your engine minus muffler? (the OS 160 is exactly 2 lbs). Was the A/C weigh exactly 10 lbs? What size is the supplied fuel tank? Does it look like the fuel tank area could be enlarged to accept a larger tank? (I'm concerned about having enough fuel). Are your aileron/elevator servos digital?

My configuration will be grossly overpowered (3.7 hp rated). However, I have a 60 size Uproar that weights 7 lbs 3oz with a Saito 100 and 15x6 prop. It won't even sit still on the runway, but boy does it fly. It takes about 10 ft of runway with a lite headwind and lands like a butterfly with sore feet (although gusty crosswinds can be troublesome). The biggest tank I can fit in is 14oz - which means I gotta watch the clock. So, I kind of know what I'm getting into here with the Yak.

Steve