Georg, I'm a beginning pattern pilot so take my advice with a grain of salt:
I got this plane (last month?) and read through this entire thread, twice. The majority of people are using OS 120 two stroke, Saito 125 four stroke, and YS 110 four stroke. I was thinking of getting an OS 120 four stroke but after reading through was talked out of it. I fly it with the 120AX, which is PLENTY of power, but after flying it this way I wouldn't want any less.

You mentioned "I am just hoping that the 115 will give enough performance to give realistic pattern performance." and if you are talking about competing, your plane will be overpowered by most of your competition. If you're just talking about basic pattern loops and rolls with not much action in your uplines, then maybe you'd be perfectly happy.

Lately I've been trying not to give advice as my experience is pretty limited, but I just maidened my Venus 40 with an OS 46AX and am disappointed by the lack of power. I'm writing this because I'd hate for you to get this heavy 8-9lb "90" size plane and be disappointed that your 115 wouldn't be enough. I've been disappointed with a couple of planes this summer and to me that's like the worst thing ever.

The engines you list are good ones. But I'm curious why you leave us with the impression that the OS 120FS would not be a good choice. My Venus II started life with a Saito 125 and after 20 flights I was so disappointed I pulled it and installed my OS 120FS. I got 500 MORE rpm's on less fuel with the OS. I also have a YS 1.10 in another plane and the OS will turn within 200 rpm's of the 1.10.

I've been flying my Venus II / OS 120FS for over 300 flights and the OS 120FS is an excellent choice.

I have the Saito 150 that I recovered from my crashed Yak.
I was considering using a 120 I have but the Saito 150 weighs the same as the 120 and is lighter than the OS 120FSby 2 oz.
I will not use a 2-stroke inverted so the 150 has worked out perfectly.
Garcfield is correct about the power. On several pattern maneuvers, I need all the power I have. You need to learn how to manage your throttle between passes to conserve fuel.
What we are saying is don't under power a pattern plane.

I originally had an OS 46 on my Venus 40 but the Os 50 was much better and the 55 would be great.

Don, remember writing this? I was going to get the OS four stroke and saw this, and didn't want to wish I had gotten something different. So I was between the YS110 and the 120AX, and with no four stroke experience under my belt I went with the 120AX, which was the perfect choice for me.

Yes I remember BUT I actually had the YS 1.10 at that point and had never run it yet. I now have it in a Sig Mayhem and am a bit disappointed with the power in comparision to the OS. I thought it would be much better than it is.

My point was not to say that the YS would not be a better choice from the git go but that the OS 120 FS is not a bad choice either. I had considered swapping the OS for the YS but now that I am running both side by side I would not go to the trouble to do so. I also have added 3 ozs. to the tail lately and it has help quite a bit with the balance. As far as the OS 120 2-stroke goes I'm sure it is lighter and more powerful than either the 1.10 or 120 FS but ( and don't take this personally ) I just cannot "tune" my ear to a 2 - stroke.

Well good to hear that the 120 four stroke IS enough. It's just an awesome plane. No regrets with the 120AX, that's for sure

I would not select OS FS engines for VII because of the weight and the price (Tower Hobbies):

OS FS II 120: total weight = 944g, $379
OS FS III 120: total weight = 1000g, $419

For comparison, YS 110S, which is also a 4-stroke, does better in either areas:
ys 110: total weight = 730g, $359 (central hobbies)


OS 120AX is a 2-stroke engine. Total weight = 866g @ $269. 120AX is about 4.7 oz heavier than YS110S, and may need extra balance weight at the tail.

I may choose 120AX next time for my 2nd VII.

But I realize VII is a pattern ship and to be able to fly sequences well either during practice and competition, light weight and engine's throttle response are the key. YS110s are excellent in either. Some extra bonus: the engine noise is under 96db with the stock muffler, and the tank can be put at CG.

Just some extra points to consider.

Hi nonstoprc,

Weight and price were the issues in my joice of an OS 120 AX. Also, like gaRCfield, I lack 4s experience.

When I did my research, I found the OS 120 AX weight to be less than most and depending on muffler, no more than any other suitable motor.
Used RCU to research weights (attached).
I have weighed the OS 120 AX (post #977) which confirms RCU numbers. Has anyone weighed the 1.10 FZ? and what is the power rating?

Must say, I never considered the noise level (db) - I'll always bear that in mind in future - thanks for pointing it out. Thats what I like about RCU - experienced modelers like yourself, Don M and many others povide so much input for newcomers like myself - and then other newcomers like gaRCfield add their experience and enthusiasm - its like a daily crash course - many thanks to all of you.
I gave the tank over CG issue a little thought with the conclusion that 1) with my still low skill level it might not make much difference and 2) I could revert to a Perry pump if need be for a small weight penalty.

As a beginner I struggled with the tank at CG and the pump - too many variables for me. Installing tank at CG is easy to do later once you get the plane flying properly and the engine running well. I now have tank in front of plane and pump on the shelf.

I learned from a pro at my last pattern meet that the best way to set up a pump is to get the engine dialed in without it - find where the needle settings are then tune the pump to the dialed in engine. Makes a lot of sense, but would in this case require the engine being broken in with fuel tank in front of plane, then moved back once engine is broken in.

This plane kicks a**.

See. Keep it simple. That's what I told you (and I guess Rick did too). The tank on the C.G, is really not necessary for Sportsman. Your sequence is so short, the C.G. doesn't reallly change that much since you don't burn very much fuel. It's MORE important to have a reliable engine. Don't worry, the Perry pump will work fine for you when you're ready to try it again. I run them on my 160's without any problems. Once they're set, you're good to go. You do it exactly like I said: find out where the engine runs happily without the pump (I usually do this on a test stand with the tank close to the engine) then put the engine in the plane and set the pump so that the main needle is in the same spot as when the engine was running without the pump. Works every time. For the 160 this is about 1 - 1.5 turns open by the way. YMMV.

John Pavlick
Team Black Magic, Tech-Aero Designs

I have two questions which I didn't find a answer to in this thread, so if you guys could help me out I would appreciate it.
The first question is when using a hyde soft mount # HCMYS110A with a YS 110FZ can you get the correct spacing of the engine thrust washer to firewall distance of 6.25 " as show in the Venus II manual ? An if so what modifications do you need to make to either the firewall or the mount to get this 6.25 " spacing ?
The second question I have is what is the diameter of the backplate of the supplied spinner that comes with the Venus II ?
Thanks
Georg

sent pm. also look at post 648 on here.

I just installed this mount / engine in another plane. It is 5.5" from back of the mount to the face of the drive washer. I needed 5.75 so I cut a piece of 1/4" plywood and installed between mount and firewall. You will need something 3/4" thick to get your spacing. If it was me I would put 3 pieces of 1/4" carbon fiber together because of the lightness of CF but just about anything will do that is ridgid enough even CA soaked, laminated 1/4" balsa will do.

Thanks guys just the info. I was looking for.

After flying heavy "metal" for a bit, I have been knocking around a Kaos arf and having a ball. Puchased a Venus 40 with a OS 55AX doing the work. Way cool whats up with that Knife edge . Now the question. Ordered a Venus II have no spare engines around cept' a OS FS 120FS thats in a P51 down for wing parts. HOWEVER, I do have a OS 2.0 FS from a Giant Super Sportster I sold on the shelf.

With good throttle management, you don't think I could "shoehorn" that big 4 stroke in there Dimension wise its real close. and I read a few posts of 1.80 four strokes in some Venus II's.

Besides excess fuel consumption, added wear on the airframe and scaring the hell out of my clubs safety officer. Is this a bad idea? or should I just pull the 1.20FS out of the P51 and go fly?

Best regards

~johnny

That thing'll beat the crap out of the fire glue joints (well, ALL the glue joints) and the all-up weight will go WAY up due to the engine and all the lead you'll need to balance it.

[ul][*] Weight also means it'll stall at a higher speed, which will make landing runs longer and much faster. [*] Weight will also ruin it's very nice, low, wing loading. [*] You'll need to shoe-horn a bigger tank in there but since a Dubro 16oz is already the width of the fuse you'll have to find one that's longer.[*] Oh, and more fuel means EVEN MORE WEIGHT...[/ul]
In conclusion:
DOn't worry though, it's not a bad idea...It's a a horrible one!
Listen to your safety officer!
You will LOVE the way it flies with the FS120.

I agree pappy, its a bad idea. But it was a fun one [8D] I'll go with the FS 120

Thanks for the sanity check...

I apologize for being lazy, but to save me the time of going through 40+ pages of posts, could somebody tell me what the ideal EXPO rates should be on the Venus II? There is nothing indicated in the instruction manual. Also, I could use some info on the ideal balance point. Right now I have it set per the manual at 6 1/2 inches.

Thanks!!
Bob

tigers650.
Expo is usually a person preference bast on one flying skill and feel. However. Here is what I do. I set up the low rates on the Venus II as suggested with -15% on the Ailerons, 20% on the rudder and elevator. I like a little softer stick center for landings and take-offs. My Mid-rates are a little more throw with very little Expo, 10%, for pattern flying. The same for high rates, which I rarely use??, with no expo.
I have played with Low and Mid rates depending on the maneuver. Example I want very little aileron throw for slow rolls. I use higher rudder throws for deadhead stalls. Softer rudder throws so corrections aren't noticeable
I guess the best is to use more expo as you learn the Venus II then adjust as you go.

Expo:
After 4 Venus II's and thousands of flights, i still do not use any expo at all. Best to fly it without and then experiment with some expo and see how you like it.

CG
As far as the CG I have always kept mine at 6 1/2 inches as the manual says and it flys perfect there.

Codfish and Tomtreese, thanks for your input. I think I will try a few flights without any expo and then decide whether
any is necessary. I really appreciate yor responses!!

What have people been using for throws (high and low rates) for this plane? Any differential?

Also what do you use to measure this with? I'm tired of using a ruler and could use some guidance on what to get.

Thanks.

GaRcfield.
I use a Great PLanes Accu-Throw meter ,GPMR2405, as well as a golf club "Loft & Lie angle indicator". This is a device, about 5" in size with two square magnetic sides and the remaining 180* is round with a 360* dial. You lay the flat side on the deflected surface and read the angle off of the dial. http://www.golfworks.com/product.aQ_...RO_A_cn_E_1894 Most retail golf shops or Dick's should have these.
Or a machinist's protractor. http://www.golfworks.com/product.aQ_pn_E_GP_A_cn_E_1894.
I use the meter or compass to set the original recommended throws, then adjust from then on with the (%) throws in the transmitter.

As I stated on the original post. Exponential is a personal preference. Less experienced pilots may need 30 to 50% to soften the thrown around the middle especially for those initial landings. Most advanced will use very little or no Expo. because they want imediate feedback and response. ie. Hovering.

The rates stated in the manual are pretty good. I use high rates on the elevator, low on rudder and I have 3 rates on the ailerons. I prefer the middle rate on the aileron which is somewhere between the manual's stated low and high rates. One word of caution, MAKE SURE YOU ARE ON LOW RATES ON THE AILERONS FOR THE FIRST FEW FLIGHTS! It is best to also be on low rates on ele and rudder for first few flights.

As a side note, you will find the venus easier to fly than a trainer, I know, i train newbies at the field and thier trainers are harder to fly. just that it does not have self correcdting features, but i find no self correction to be of benifit for beginners.

Yeah I'm finding no need for such high rates on the ailerons. I recently heard that full deflection should be used to execute rolls, so was thinking of incorporating that into my low rates, leaving high rates for bailing out of situations. I'm also finding that I need more throw in the rudder for stall turns, but could be related to my 4.8 volt battery and DS821's. Will be switching to 6 volts for next season.

Are you guys setting up aileron differential? I haven't played with that yet but not sure if I should be bothering yet.