Prop Load: compare Vess 27A to TBM 28x10

[dmcquinn]

I've been running a Vess 27A on my Da 100 and like its performance. But I broke it and put on a TroyBuiltModels 28x10 prop (because it was available).

I was surprised at the difference in max rpm:

6600 on Vess 27A
5300 rpm on TBM 28x10

The overall pull of the TBM was still good -- for example, I could hover at about the same throttle setting. Just surprising (to me) how much more load this prop put on the engine. The TBM prop looks similar to a NX or Xoar.

The TBM seemed a lot quieter, too.

[krayzc]

wow

[BTerry]

It will absolutely be quieter if the RPMs dropped that much!

In my experience the TBM props load about as much as MSC props, which is to say very high. That TBM 28x10 is a similar load to a 30x10 mejzlik.

[claselva31]

Hey Guys I've been running a Vess 27A on my PAU Ultimate. The prop has been a great performer, especially on this airframe.
Before that I ran a PAU Laminated 27*10 , VESS 27B, 3W 26*10, and now I am going to try a TBM 27*10 to see how they all compare to each other.
The prop on initial view seems like the same basic shape as a Xoar prop. The one thing I like is it's not as fragile as the Vess. The Vess's tips are extremely thin and can be broken in transit moving the plane in and out of the truck. The TBM is a more robust prop without the weight of a laminated prop.
I'm going to gather all my props and do some testing at the field this week. I'll try to get everything from weights to max RPM's. I also use this fish scale tied between the table and the plane to test the static thrust of each prop. Let's face it if it pulls harder on the ground it should pull harder in the air. I'll get back to you this week. Chris L

[customjrod]

I would like to see those thrust #s my self.

[claselva31]

Hey guys I've got some info for you on prop combos with a DA100. Our field is at 400 above sea level and the temp was 73F winds from SSE at 10 gusts to 15MPH. That out of the way here we go.
Props that I tested were a 1) 3W 26*10
2) Vess 27A
3) PAU 27*10 (Laminated)
4) PAU 28*10 (Laminated)
5) TBM 27*10
All tests were done without changing the throttle setting or idle setting at all, a decible meter was placed at 9' away (granted in the grass not as accurate as on concrete).
Results: Idle RPM Full Throttle Decibles at 9' Full Throttle
1) 1600 1) 6669 1) 109db
2) 1600 2) 6500 2) 106db
3) 1620 3) 6270 3) 108db
4) 1440 4) 5550 4) 107db
5) 1410 5) 5700 5) 108db

Spool Up
1) slow
2) quick
3) quick
4) very slow
5) quick

Real world results: mind you this is on a PAU 37% Ultimate Bipe. 30lbs
The PAU 27*10 flew the plane good. Nice vertical up lines, got a little slow at the top of giant loops doing Cuban 8's, good on landing. Would hover at 50-55% power.
The Vess made the plane come alive with performance. Awesome vertical performance, no slowing at top of loops, not even packing 64 oz of fuel and smoke on board. Hover at 30-35% power.
The 3W I wanted to land after I took off an made three revolutions of the field. I use it to spread peanut butter on my kids sandwiches now. Enough said!
The PAU 28*10 was just too much prop for the engine and airframe combo. Very sluggish, slow to spool up. Got the engine hot faster... Didn't bother Hovering.
The TBM 27*10 flew the the plane second best to the VESS prop. Good vertical performance, responsive throttle,great on landing. Hover at 35-40% power.
Had you never flown the plane with the Vess and went with the TBM you would be very pleased. The big differences to me is two fold. One the Vess is a very fragile prop (especially at the tips) and can be broken in transit. (Yeah you never did that before). Second the TBM is $12 less expensive and is more durable. Bill Hatcher and the guys at Troy Built will usually have the prop out to me in 2-3 days shipping, very reasonible. DA gets $53.00 and $10 for shipping and usually get in 4-5 days.
In the end the Vess takes 1st in performance.
Second goes to TBM.
Third PAU 27*10 ( I wouldn't mount the 28*10 unless I was flying a barge).
Fourth by far the 3W.
Hope that helps Guys Chris

[krayzc]

Thanks for the scoop!

[Zee]

Now if you would have thrust with the figures of RPM that would mean something. RPM on its own would not tell much, RPM with amount of thrust developed will tell you which prop will pull more.
Best way to do it is attach fishing type scale to the tail of the airplane and to fixed oject( fance post , trailer hitch on your car, etc.)than watch the scale as you apply full power. That will tell you how much thrust the engine/prop combination will develop. That is the number you want to know. you will need good scale up to 80-100 Lb.
Zee

[claselva31]

Zee I went out with a scale but somehow it was broken. I agree with the coment you made on having that info to validate the RPM's but I was the one using my calf's to hold on to her. The Vess pulled the hardest by far, the TBM second PAU 27*10 third, 3W 26*10 fourth and last was the PAU 28*10. I'll pick a new scale to verify those numbers.

[Skippykix]

Chris, Thanks for the info. I'm currently building the PAU Ultimate with the exact same setup as yours. I was woundering how a Vess 27A would pull around this setup and now I know. Again thanks. Skip.

[claselva31]

Hey Skip do yourself a favor and get one or two 27*10 TBM's and break it in on those. Also if you nose over and smack one like I did 3 weeks ago (my Vess) it doesn't cost you $65.00. The wind blew up my tail while I was sitting at the end of the runway (talking to my spotter not looking at the plane.It was stopped and idling) and lifted the tail and just lightly touched the tip, but enough to have to throw it away. email me if you want to discuss that bulid or what I did to mine.

[smokin]

i agree that the vess props are the bomb! they really are fragile though!

i had a 3w 28-10 on my 2.6m comp yak with a 3w106 and it was alright... i switched to a vess 28b and OH BOY!!!!!!!! what a power difference. the vess props are quite simply....bolt on h.p.!!!!!!!! make sure you use prop covers with them as they WILL be damaged in transit if you aren't really cautious.

just my $.02

[Skippykix]

Chris, Thanks for the info. Below is my set up so far:

- DA-100 (already broke in and just came back from a DA check up). Compact mufflers.
- Hitec 5955's everywhere. Airwild servo arms. (Rudder servos are mounted in the tail for better rudder control
and will also help with the weight distro).
- Smartfly power expander
- Smartfly turbo reg
- JR 1221 reciever
- Kevlar flying wires
- Custom ordered C/F landing gear from Graph-Tec
- J&J tail wheel
- Fromeco 5200X2 REC and 1X2600 IGN for batteries
- B&B 32 oz fuel tank
- C/F wing tubes (4X40 blind nutes installed on small pieces of balsa and then epoxied inside the tubes)

I pretty much threw out the instructions after page 5 and have been taking it one section at a time. Wings and all tail surfaces hinged and sealed. Servos installed except for the throttle. Firewall installed and pinned, still waiting to put on the Kevlar for strength. Wings are set up with zero degree inc on the lower and -1.5 deg on the top. The only other mod I did was to run a piece of 4X40 threaded rod through the fuesalage where the lower flying wires mount. A flying buddy of mine had one of these and he said that the sides of the fues would pull out from the tension of the wires. So now they just pull on each other. I'm currently deployed to El Salvador til the middle of Dec so the finish on my build is at a stand still. Any other advise you can give would be greatly welcomed. Thanks......Skip.

[claselva31]

Skippykix,
Thanks for your service to this country first and formost. As for the plane sounds like you have it licked. I haven't had any problems with my flying wire mounts. I'll send pick of what I did. I leave the wires on the plane and just place them in the fuse when I'm done. A piece of fuel tubing on the bolt and you don't even need to store them. I just unscrew them slip the tube on and drop them down in the fuse and put the conopy back on. As for the balance this is a pic of my set up. I have one 8711 on the rudder and can do knife edge loops all day on a pull pull. Hey do yourself a favor and order a carb plate from TroyBuilt models. I had a problem at first with the air coming in the cowl and slamming into the carb diaphram causing the carb to flutter. The plate fixed that and made a damn forcing the air to go around the plate not allowing it to screwing up the venturi of the carb. Hope that helps. Chris