capthis

My Feedback: (67)

See here is the stock standoffs that come with the kit.

Maudib

My Feedback: (51)

Here is an enhanced version...

Looks like:

185 mm is the outside diameter of the engine box... my measurement concurs.

52 mm from the INSIDE of the fuse side (not tri stock or outside of fuse side) to the center of the first pair of vertical holes
70 mm from that point to the center of the 2nd pair of vertical holes
31 mm down from the TOP of the firewall (not a slot bottom but from tounge top) is center of top pair of holes
80 more down from there is center of bottom two holes.


For measuring accuracy I would ADD 31+80= 11mm and measure from the same "zero" in this case the top of a firewall tounge

Same with the 52+70=122mm from the left of the inside of the fuse side.


This is assuming it is correct for the 3W 106 engine (whose bolt patter is in fact the 70mm wide by 80mm tall)

The engine is stated to be 183.5mm from back of engine to prop hub 7.224388 inches +.75 " for standoffs = 7.974 (which is close enough to 8" for me)

If the drawing is correct then the offset used was 13.5mm (total width 185/2=92.5mm actual centerline) (52+ (70/2))=offset centerline for QQ3W106 = 87mm

A difference of 5.5 mm or 1.41 degrees right thrust. THOUGH my builders protractor reads about 2.5 or so degrees of right thrust in the firewall.....

I suppose a call or e-mail to QQ would result in the intended right thrust...


By taking taking a measurement of your YOUR right thrust in your firewall and the length of YOUR engine from firewall to prophub you can calcuate the distance of offset centerline to measure using a tool on our clubs site here:

[link=http://www.lcrcc.net/offset_calc.htm]Engine Offset Calculator[/link]

Simply determine the amount you want your prop hub to protrude from the cowling, subtract the engines length anf VIOLA the length of standoffs needed.

The cowl is approx. 13 7/8" long minus the approx 1/4" front former thickness (that you will over lap) minus the approx 6 5/8 of engine box length and you are left with 7" exactly to get the from the firewall to FLUSH with the front of the cowl...

Add XX" you want the prop hub to stick out and that is the length you want. Subtract Engine back to prob hub distance and you now hane your standoff lengths

Right thrust is already built inthe firewall. So all standoffs will be the same length.


DP... according to this you should be sitting 1" out from the outermost part of the cowl Lay a straight edge across the nose and up gainst the shaft of the engine and see how much the prop back is out from it.

The scale Yak had the prop out there pretty good...


Also I have made it an effort on other projects to drill the little pilot holes and use long course drywall screws to temp attach the engine/standoffs , then see how the cowl fits/looks

woodscra

My Feedback: (23)

Wayne, what is your final weight? Would you please write what you have in it for reference?

Thanks

capthis

My Feedback: (67)

My motor is mounted now, and it appears to be centered in the cowl prett well, so I am pleased with it. But the instructions were way lacking. I still wonder if your 52mm measurement should be 62mm, as I think that what I used, after studying the picture for a long time!

capthis

My Feedback: (67)

Oh, and a DA is about 6 9/16 inches long to the back of the thrust washer.

DA is roughly 6.5 inches long
3w is roughly 7.2 inches long

Best I can figure anyway!

famousdave

My Feedback: (61)

Well I went back to work after I ate dinner and had a beer... I was much more rational. I took out the 3/4" standoffs and put in 1/4" I shortened the pipes just slightly and everything went together no sweat. The rear cylinder is a little close to the firewall, but I don't think it will effect cooling.

The prop flange is now about 3/4 inch out and it looks about right.


As far as the picture / dimensions to mount the engine - I downloaded the PDF from the site and expanded it with a 200% zoom and it was easy to read then. My center is dead on.

Man this plane looks nice all put together. BTW - the replacement gear I got from Wayne was 100% better than the first. They splay a little, but I can easily put the pants on now without them scraping. I think the slight flex will go a long way to relieve stress on the airframe...

DP

johnmann

I flew mine yesterday for the first flight and it flies great. The wind was blowing about 20 knots so didn't get to do much, but what I did was nice. I just took the supplied canopy bolts and ground the head dia. down on a bench grinder spinning them with my fingers until they went in the holes. The back two I had to lower the blind nuts and grinding a point on the bolts well help them start into the blind nuts better. My DA fits perfect with the supplied standoffs and I used the measurements that is in the picture posted back a ways, you can get it off the web site for the larger yak. I had some pretty bumpy landings in the wind and am not at all worried about the strength of the fiberglass supplied gear it worked just great. Since I didn't put lithium batteries in and like to charge after each flight, I just cut snug openings below the canopy in the fuse and through the foam and foam safe CA'd my switches with charge jack in and worked great, beats taking the canopy off to charge. I am going to add some little pieces of ply in the back bottom corners of the canopy and glue some little dowels in hanging down and locat matching holes in the fuse because the canopy vibrates quite a bit at the rear former against the turtle deck,which I don't want the wear on the turtle deck covering.

Maudib

My Feedback: (51)

Mine will be getting dual hatch latches from Hobby Lobby

I'll be putting two or three indexing pins in the front former and canopy, then using one of these on each side of the turtledeck.


Here's the install on my 87" Yak...

H. Wayne S

My Feedback: (18)

Woodscra, final weight. 25lbs, 6 oz.
Used 8611As' on rudder (2 in a SWB servo tray w/arm) and elevators. and 5945s' for the ailerons. Futaba 3305s' for throttle and choke. two 4500 nimh batteries for Rx. one 2700 for ign. ZDZ 100 with stock pipes, 4 1/2" lightened Tru-Turn 26 X 10 Bambula wood prop, TME smoke system.
I had to place all three batteries in the engine box to balance the plane at the recommended CG.
Never thought I would get it to balance, the ZDZ is lighter than the DA or 3W but I did not think it was that light.
I did add two alum struts to the landing gear for piece of mind, and I closed the front of the fuse to keep air out and blowing the canopy off.
To be frank, I was a little disappointed in this plane, I expected better from QQ & Wayne. Just to add to the build problems, the covering has wrinkled very badly on the fuse and when I heat it with a heat gun to smooth things out, in less than 5 minutes ther are back. Yes I go over the covering with an iron after I smooth it out with the gun. Funny, when it arrived there was not a wrinkle on it.
Can't waite for Saturday, I gona fly this sucker tomorrow, Friday !

dp-good luck, Have another beer, hang in there. I wanted to trash mine several times before I completed it.



Last thing one wants to say at the field. "Are those my fingers laying on the ground"?

Maudib

My Feedback: (51)

It's amazing the differing opinons on the quality of this plane...

I've built custom aircraft from plans, many kits and countless ARFS and this one is tied or surpassed only by the EF 87" Yak. Hangar 9 stuff is right up there too.

Though I have yet to build it, it all fit nicely, was in excellent condition, looks to be built VERY well...

And most of all... you said 25 lbs 6 oz... On a plane his size...

AND you have dual receiver batteries, cannisters, SWB servo tray, a pretty large ignition battery, aluminum spinner and a smoke system with tank?

Whoowheee! That sure sounds like the 100cc plane of the century!

(It does look like the ZDZ100NG is 1 lb lighter than the DA) I have a BlueHead coming and another NG in a BME Ultimate.

I really want to put the BME 110 in this plane, but I guess I better watch balance... At another lb lighter than the ZDZ, I'll have to maybe move the pull system up a ways. I'll be using 5945's in the tail which will save me .6 oz in the tail... that ought to save me close to 3 in the nose...

I guess we'll have to see... If I really need the weight, I'll use a Powerbox in there with redundant batteries and still end up at less less than 25 lbs...

famousdave

My Feedback: (61)

Maudib - I was not bashing this per se, just pointing out a few frustrations. I still think it is the best ARF I have come across, including even the EF Yak. There are many things about this plane that are better than the EF (mainly aesthetics) . I am just not an ARF guy, so I tend to find fault where others may not. If this stuff happened on a kit I was building I probably would not have thought twice about it... Some of the disappointment was my fault as I built ahead expecting this plane to be 100% out of the box perfect. For the most part it was, but the the few issues that did come up made me have to re-do things I already had completed. They could have been prevented, especially the prolinks, hatch and landing gear problems.

I too sealed off the rear openings in the cannister box to prevent air pressure buildup under the canopy.

I don't like the canopy mounts either. I have not installed the canopy yet as I am trying to come up with an easy-off solution that still provides rigidity to the structure. I have some ideas, now I just need some time! I will probably use the existing system, just my own hardware.

Overall I am very happy with the plane, if the few quirks could have been avoided this would have been a perfect 10. I think mine is going to weigh right at 26.4 pounds with the 3W, a very respectable weight. I had no balance problems at all with mine and I use the Powerbox 40/20 and 8611s all around.

She might get her maiden this weekend, we shall see...

DP

rmh

I am running the zdz50 in my EFYAK-and have the zdz 80 in a reworked WH 35% EXTRA- UNDER 26 lbs.
clipped wings and 1960 squares now.
Both engines have the AMT pipes
for power per dollar or weight - awfully hard to equal
If I were doing this big YAK- it would have the 80 on the pipe .
Locally we have done ZDZ100NG on AMT pipes aprox 7000 rpm on Mejzlic 26x10- DA100 on KS full pipes again, aprox 7000 on Mejzlic 26x10 and the ZDZ80 on AMT full pipe.
The differences in the three setups is minor - all start /run easily /pull very hard.
BUT-if you run in cowl muffs - the power shifts to the DA100- then the ZDZ100 then the 80 .
If a plane has setup for pipes and you don't use em - you are missing out .

Quique Somenzini

Hi Everybody I am Quique, I do not get too often to forum as you probably noticed. Friend of mine called us and told us about this threat.
I've been reading and I need to do some comments that hopefully you will find useful.
I must apologize you for having few problems during the building process. There are issues that are minor and isolated, obviously they are problems that should not be there but unfortunately are there. Thank you for the effort on surpassing them. However there are other that are more concerning to you and I would like to share my thoughts and experience with you all and hopefully this will help you to understand better this matters.

Landing gear:
The landing gear you are receiving with the airplane is the gear I choose after testing a total of 4 different gears and the one you have it is the best one.
There are two schools, one school likes flexible gear and the other more rigid. We are in the first group. We believe the gear is the one that should be absorbing the vibration and energies the airplane takes during take off and landings, as well in case of a extreme hard landing the gear is the one that should brake first acting as a fuse for the airplane, I prefer much more in case of extreme hard landing to brake the gear and not the gear mount or airplane.
I had many flights on my airplanes and I fly from a rough grass runway. I did have also one time an emergency running out of gas on a bad position and I real hard landed my airplane and thanks to the gear the airplane was not damage.
I will ask to the owners of our Yak 102!QUOT! to give us the chance and fly the airplane with the gear we are supplying. The gear is a lot stronger than what it appears. It may confuse you specially if you check the gear without been mounted on the airplane. The two center mount bolts makes a big difference.

Canopy:
I am sorry about some of you have problems with the canopy being too long, I am not happy with that and I am trying to find and answer. Two could be the answers. One the canopy was not built right and second perhaps the fuselage shrunk. In China the humidity is extremely high and it is very possible the fuselage could shrunk being at dryer air. Will not take much to make the canopy to not fit the fuselage, the rear former of the canopy is angled, so a small change in length wise will mean big gap at canopy base.

VERY IMPORTANT
Along with the airplane Wayne shipped an additional information sheet that I will encourage you to read closely. Also i will post tody at our site www.somenzini.com, 102" page under information.
Point #2 on this sheet is very important to follow for the good life of your canopy. If you do not have that paper with you anymore let me tell what is point #2. We talk about the importance of the installation of a rear pin in the canopy. This pin is very important for the good life of the canopy. I found on mine at beginning of my test the canopy was shaking too much at idle at the rear portion of the canopy, just behind the two rear canopy's bolt. I installed a pin as you can see the pictures, this pin is a rod of carbon fiber I believe 5 mm, I glue it to the fuselage and I made a hole in the canopy frame as you see the picture. Then I feel the hole with a bit of thin C/A to make the plywood stronger.




This is very important for the life of the canopy, if you do not put it the canopy might crack.

VERY IMPORTANT 2
Also and lately I did put silicone in the inner edge along the entire canopy (from front to rear), the inner edge that I mean is made by the plywood canopy frame and the canopy plastic. By putting silicone at that edge, it gives to that corner a radious and not being so sharp helping big time to extend the canopy life. Please see graphic below.

Cowl Length
I read on the threat about cowl length. The pictures I am seeing posted are just fine. My airplane is exactly the same. We did this in purpose as we did in the TOC Yak54. We found by moving the engine forward we gained performance, it seems the prop works better and as result of that it pulls better.
On the 102!QUOT! we tried to do same thing so that is the reason the motor is positioned as it is and I think it does not look so far from scale. All our Yaks are the same, the 72" and the new 85" for 50cc that is coming soon.

Sorry for my long writing, time allowing I be more active at this threat and try to help you out more and share with you my own experience with the 102!QUOT! .
Thank you.

Quique Somenzini

Maudib

My Feedback: (51)

Didn't mean to insinutate you were... just noticed the various peeves / probelms people were having and realized which were important to me and which weren't. We all see things differently. I do recall you giving the BME Edge a rather scrupulous going over and finding alot there.

I will admit though... at $1200 a person should have to pay another $100 for a "Dubro" hardware kit, or go buy $XX worth of titanium links to replace what the kit came with. It comes at a high price, and I suppose peopl ehave a right to complain about such things.

Good lick on getting out to maiden... hope the weather is perfect!

Maudib

My Feedback: (51)

Thank you QuiQue for becoming part of this thread. I think overall you'll find most f us very pleased overall with the 102" Yak and look forward to your input regarding people's questions and concerns. I've heard many time that Wayne is doing an excellent job of taking care of customer problems and that goes a long way too.


Would you care to comment on the overly long 2.5" pushrods for the ailreons and elvevators? Were yours 2.5" and if so how'd you get them to fit?

If they were 2" does Wayne have stock of them to repace the 2.5" ones?

Again welcome to this thread and also a quick note to say how much I enjoy and admire your piloting skills. Beautiful flying!

famousdave

My Feedback: (61)

Thanks QuiQue for the excellent explanation. I think you hit the canopy issue right on - I am sure the fuse shrank slightly, that also would explain why the covering loosened up on some planes. I don't think that is too bad of an issue at all.

My first set of gear were weak, now that Wayne sent me another set, they are perfect. Flexible as you state, and you are right - I'de rather have the gear fail on hard landing than have the fuselage destroyed when the gear block gets torn out.

I noticed the canopy attach was a little loose, so I will use your suggestion of pinning the rear of it.


My engine crank protruded a little more than 1.5" (33mm) from the cowl - are you saying that is how yours is??? If I look at your pictures on the website it does not look like the spinner is THAT far away from the cowl. I reduced the 3/4" standoffs to 1/4 and I still have a GOOD 3/4" of crank coming out of the cowl. I usually have less than 5mm on most of my planes so 18mm is still a lot as far as I am concerned. I also noticed where you cut the cowl from those pics. I would have had to cut much more away had I kept the 3/4" standoffs so I still think the engine on mine was probably too far forward.

I understand the need to bring the prop out a little for better prop performance, but honestly, it looked really funny with the larger standoffs. The engine looked like it was half way out of the cowl or at the least like the engine was way too big. I could not live with it. I think with 3/4" (18mm) prop clearance there should still be good prop performance and cooling - would you agree with this??

Anyway, thanks to both you and Wayne for the hard work and support. This is a great model and we all cannot wait to fly it.


DP

Quique Somenzini

On the titanium rods let me answer you later today on as I am checking this matter right now.

About the cowl I just checked my airplane and I took a picture as you see below. It measures 43 mm from the black front plate of the cowl to the front edge of the engine hub.
You have to consider that if you move 1/2!QUOT! back your engine you will change the CG, I do not exactly how much but it will be an amount to consider due the engine weights about 25% of the total weight of the airplane. Also remember when you move the engine you are moving also the canisters and all ads up.
I do not think the airplane performance will change significally, I mean pulling performance wise because it is small amount and the prop still far enough.
I learn with the years that looks is very important and it is very important that you do like your airplane or details that you have on it, this is inspirational and motivating for you about the airplane. So if you like it better do it, just check carefully the CG.
When I flew my Yak for first time back in 2002 for TOC I will tell you that I did not like much the engine being so far out, with the time I got used and I learn how much better it flew in that way but I felt even better when I saw a full size Yak54.

splais

My Feedback: (25)

Mes, did it fly better because of the CG change or because the added distance helped airflow off prop.

Quique Somenzini

Splais,
Sorry for not sign my last post, but I am Quique.
The motor is not further out because the CG purpose is because prop performance. I learned this years back when I flew in pattern an airplane called Desafio 2000 that was a scale down of the Sukoi, so a round cowl airplane. By that time power was not as good it is now an a little bit here and little bit there was the way to get the power, now still that way but what what we think now is not power back in those year was big power!.
I designed the 102" intentionally with the motor in that location for best prop performance, so the CG is right with the motor at that location, so if you change the motor location you'll change the CG.
Hope I am clear. Take care Quique

famousdave

My Feedback: (61)

QuiQue,
Thanks for the explanation, I have left the standoffs per the manual and it looks OK.

I like your hangar!!

BTW - Congratulations on the launch of your new company. I wish you and Wayne the greatest success! Your personal involvement and support makes a huge difference for all of us.

DP

John Murdoch

My Feedback: (11)

Quique.. First I'd like to start by saying, I too admire you, your airplanes, your flying style and your overall personality. We here on RCU should feel lucky to have a man of your statue chime in and make recomendations/suggestions.

I know this is your Yak thread but I have a question for you regarding any round cowled airplane. Are you saying that the performance for the prop is better or significantly different if the prop is out further or in further, either way? Other than the try it, then try it again in a different location, is there a rule of thumb for the proper placement of an engine/prop location for a round cowled airplane for the best, overall performance?

Again, I am honored that you would take the time to help others.

Quique Somenzini

I appreciate very much your kind words. Time allowing me I will try to be at this threat supporting our Yak 54 102" I am glad to know I can help you out some with my comments, you know in the model airplane world there is so many way to looks things that I can not say I am right in all my comments, my only intention to be here at this threat is to share with you my own experience and thoughts with this particular model, I feel by this way I can save time for some of you.

About the question of the round cowl, what I found is when the prop gets too close to a big round cowl as it is the Yak54 cowl the prop loose a bit of efficiency, it is not a huge difference but enough to improve at least a bit the airplane performance. I am passing you some of the secrets that I did have!, but I thought you all need to know why. Thank you. Quique

rmh

The air directly between the cowl and the prop is simply stirring in a circle --a condition which worsens the closer the blade is to the cowl-- The prop does not blow air into the inlets on the YAK/Sukhoi radials.
This is why the YAK has the extended spinner location --to stop the blanking .
look at these pics- first is full scale craft- second -my own setup duplicating the distance-third model shot
These distances are scale -as is the 102 " model
I think it looks great -
The spinner up tight to the cowl just looks wrong (as do wheel pants ) -on the 54
But hey -it's your plane -

John Murdoch

My Feedback: (11)

Dick.. What engine are you running? What size Prop? And lastly, could you get me a measurement between the cowl and the trailing edge of the prop? Your explainations make sense. I think I mounted my motor a little too close by the looks of your pictures.

rmh

I better clarify - my YAK is a 87" model -with a ZDZ50NG-23x8 prop -absolutely ballistic.
Anyway I am looking hard at this one tho --for my new 80/pipe combo

My prop to spinner edge is 1.25"-so to be scale yours would be even more !
Look closely at the full scale - the prop is not at rear edge of spinner - -