Whiplash
 

Folks, I have a Whiplash hanging on the wall, waiting for about three hours' effort to complete the finishing job, then it's gear time. Before I sound all gung-ho, realize it has been in this state for three years or so. But now I am completing it.

Question: what are the pros (if any) and cons (I'll bet there are some) of putting a "large block" engine in these, like say an OPS .65 [sm=72_72.gif] for example. It seems the wing loading would still be okay. I imagine people have done this, no? Advice? If I did this I would definitely mold a cowl/pipe tunnel, and maybe redo the vertical stabs by blending them in aft there somewhere, not sure yet.

Thanks!

MJD

RE: Whiplash
 

Unless you have launched a Whiplash a bunch of times with a lighter engine like a Jett 45-60 FIRE or YS 45 RE, I'd pass on the OPS 60 for now. The Whiplash is heavier than the Diamond Dust. If you must try it, than wait till you have a good breeze to launch into, it's always easier to get it flying good that way.

I launch my (heavy) clipped wing DD w/DF engine pionted up at about 70* with the right wing away from me when there's no wind and it usually heads strait up after that. With a good breeze 10+mph I launch it at a lower of about 45* right wing tip down. I don't just let go, I give it a well directed push, using the exhaust coupling. Launch at 30% expo and 75% rates on aileron for the first 250' than you will need to quickly switch to 100% expo & 100% rates. This make the roll control much tighter and less over correcting at the start.

You need strong servos on the Whiplash.

Have fun, be safe.

RE: Whiplash
 

I'm not above building a bungee launcher.. I hate launch antics. Had too many people give me rotten hand launches, now I don't even trust myself :). No really, hand launching is fine but I would do a launcher for this anyways.

Got HS945MG's for it - I think they should do on 5 cells.

Thx!
MJD

RE: Whiplash
 

I used JR 8411 servos for quite a while in a Whiplash with a YS 45 and it's the minimum for that combo. The HS945 specs look to be a bit less.
Anything above a performance 45 YS to 60 Jett engine,(like a D/F or OPS) I'd use JR 8611A's or Hitec 7955TG's and the battery should be a 5 cell 2/3 A size. The AA or AAA size wont have the current for those servos for very long and when the voltage drops too low the XR stops working, game - over.

Yep, I used a launch dolley for a long time, I don't blame you if you don't want to hold on to a 2 1/2 to 5 hp meat grinder.

RE: Whiplash
 

If I do this I'll take your advice to up the servo torque. They all weigh about the same at that point anyways, the differences hardly matter. Yeah, I planned to use exactly such a pack but was thinking 1100 NiMH. Or hmm, should I just use NiCads and take a spare pack with me and a charger? (hah - that assumes I'll get more than one flight attempt in!.. :))

Okay - next question - anyone know what I'll find when I hog out the engine bearers? Not that it matters, whatever it is I'll have to deal with it but just curious..

MJD

RE: Whiplash
 

Wow....First things first, sounds like more than 3 hours of work- :D

Yes, big block engines have been done with launching success (Rossi-65 & Rossi-81DF by Chuck Auger), but I would stay away from them unless it is all you have and you wanna make a 30 second youtube clip. There is plenty of engine mount available to "widen" if you are determined to try that...

Pros of big block: Looks *****in, nobody expects success so if you fail you get credit for trying.
Cons of big block option: Makes an already heavy airframe...heavier. Can be difficult to balance and it swings bigger wood (so to speak) so launch has even more torque. Poor gas mileage.


For servos the 945MG will be fine (they are 100+ oz. @ 6V right?). I have used 645MG's (107oz. @ 4.8, and 133oz. @ 6V)on several Whips and never a problem. If it makes you feel better to buy $100 servos go ahead-

Lastly, if you are going to go to all of the trouble of cowling and fairing the engine just get an Oakdale Phenom. Regardless of what you may have heard there is nothing wrong with them

James

RE: Whiplash
 

They now make the 2/3A 1500 NiMH which is what I run, and larger cap. too.

Hi Razor!

RE: Whiplash
 

I already own the Whiplash, so the Phenom is a good idea but I'll have to work with what I have. Cowling it in would be a do-it-for-fun project. The 945's are 122oz @ 4.8V (there's no 6V rating on them), they should be fine from the sound of things.

We'll see - it's just an idea. I'm juggling around combinations of stuff I have and deciding on projects for spring.

MJD

RE: Whiplash
 

945's are 153oz, speed .12 @ 6 volts.

RE: Whiplash
 

MJD:

If you have a pic around of that bungee launcher, please post it. Have built a bunch of dollies through the years similar to Razors, but hate it when they hit a bump, ala the old hellrazor U control days. Talk about a screeming engine!!! Would love to see something of a ramp type that works well. Simply too lazy to fight through to a good design. By the way, you would not believe just how heavy that OPS 65 is, think the Jettt 90 is lighter!!.

RE: Whiplash
 

Cool, that wasn't shown on the package. That should be enough.

MJD

RE: Whiplash
 

Wow MJD I just did almost the same project putting together a whiplash that had been stored away. I think these guys are selling JETT products. They told me I had to buy one of their pipes and it was not better then stock OS and was not even comparable to mousse can.

Below are some links of my whiplash, but now has been modified with correct prop tru turn adapter and aerospace APC carbon fiber at engine mount and c/f at leading edge.

These deltas need exact CG, that means if you run a big tank, you need to make sure with the add (difference in weight) you need to stay within the CG range. I had to run 12 oz for 4 mins. I am at 2" with the add 5 ozs difference add to tank area for balancing and 2.5 empty w/o added weight. MY 3.3 hp 2 long stroke YS 91 SR with mousse can has a weight of 19 oz. To make CG I placed MG digital servos at rear tail end and centered on alierons. If you are interested I will link another picture. But it reduces flutter to have servo centered. Also used 1000 mah a123 6 volt lipo, 1500 standard lipo and regulator in tail section below fins. No weight added just moved regulator around.

I am not sure about the OPS engine you mentioned but I think big bore is the only way to go and not to worry about a small difference in engine weight. A high speed small prop is way too hard to hand launch. i am up to 20+ flights on my whiplash. When I ran the 10 10 prop, it was fast but if hand launched at steep angle (pitched to far up) it would nearly be uncontrolable till it got up to speed. I ve seen other guys encounter the same thing with hand launching deltas. I felt safe with 12 12N prop but only got 13k rpms. I am going to run a thicker hub BOLLY carbon fiber 11.25 by 8 this wkend which should hit higher rpms and be easy to launch, which works well with my tru turn prop adapter as the 91 sr was designed for helicopter.

WE flew the shark coroplast pylon combat planes and they got top speed and launched best with a combo of a 25 fx mousse and just a 8 by 5 apc prop. For hand launching you want a bit larger prop and less pitch but with high rpms you can stil get the speed.

http://www.rcuniverse.com/gallery/ga...berID%3D235242

http://www.rcuniverse.com/gallery/ga...berID%3D235242

Let me know if you want me to link and/or post if someone will tell me how from the top view. Please let me know how your project turns out. With C/f reinforcement I think this delta will last for a long time and boy is fast. Good luch

RE: Whiplash
 

I took a 2nd look at the above posts. They do have some good points. I would just be worried about CG not a few ounces of extra weight

Not too small of a prop with high pitch for hand launching, OPS is heavy and a really high speed reving engine right?

I would be embarrassed to do anything but a hand launch. But it might not be a bad idea. I only had problems launching my 5 lb whiplash when I went to the 10 10 prop apc

I have no idea how fast my whiplash flies. Wish I did. It sounded good because it could handle a larger prop, is light 19 oz, 3.3 hp, long stroke, high reving, designed for 30% nitro and was cheap for an engine with only a few flights on flea bay. They have them here too.

anyone have an idea what spd a 12 12 N apc prop at 13k rpms on a 5 lb whiplash might be flying?

I think the new bolly props should be better. Trying to decide which engine to try next. Maybe the Jett is the ticket, who knows...

RE: Whiplash
 

Hello MJD and others,

over here in Europe the purpose built speed planes powered by 10 or 11 cc RIRE speed engines often do weigh in excess of 5 lbs.

Nevertheless the take-off procedure isn’t difficult as can be seen in the small


showing OPS .60 powered purpose built speed planes weighing more than 5 lbs and exceeding 220 mph:



As we know the OPS, ROSSI, PICCO, BVM, OS etc speed and ducted fan engines have to be operated with prop diameters not exceeding 9“ to avoid too high prop tip speeds and massive loss of engine/prop efficiency. Moreover the wanted top speeds demand high pitched props exceeding 9.5“ of pitch. For that I’d take the ZINGER 11x10 wood prop (#513) and shorten it to 8.5“ of diameter.

Because of the high static rpm of your OPS 65 ducted fan engine you won’t have any trouble getting the WHIPLASH safely taken-off. But for both very relaxing and very cool [8D] take-offs I’d built a launch ramp similar to this for your Whiplash:


More about the correct operation of 10 to 15 ccm ultra high performance engines has been summerised here:





So using your OPS .65 RIRE and the ZINGER 8.5x10 prop a stock Whiplash airframe will definitely exceed true 200 mph! There’s more than suffice static thrust available with this combo...

Check out other commercially available speed plane kits and recommended engine/pipe/prop combos here



Have fun with one of the fastest possible Whiplash combos! [8D]

RE: Whiplash
 

Okay, that's the plan then, this is sounding more and more like a good idea. Time to roll up the sleeves and get to work! Hmm, I'll have one more cup of tea first though.. :)

MJD

RE: Whiplash
 

Clay- What are you talking about? Are you saying thet the Jett-Stream mufflers are not as effective as a stock OS muffler? Please clarifyI always recommend Jett products because after 25 years of this stuff, they are the best.

james

RE: Whiplash
 

I didn't think there would be too much problem, but I also will not feel girlish if I make a launcher. More consistent launches = longer life and calmer pilot.

But I really ought to drop in the .80 liner and piston, right?.. :D

MJD

RE: Whiplash
 

Well the OPS .80 cylinder housing is differently - i.e. larger - bored, so the .80 cyl/piston assy does not fit the .65/.67 housing.

But the stroke between all OPS .65/.67 and .80 is identical so is the conrod and the crank. The engine similarities (interchangeability of parts) and differences have been listed in the above linked OPS threads already...

As for OPS .65 engine spare parts you should buy a new actual 3+2+2 ports OPS .67 marine engine (non-needle bearing conrod version).

As for the tank volume (bubbless type) at least 300 ml should be considered. So the stock Whiplash’s tank compartment has to be modified slightly.

There’s still plenty of space left for the R/C mixture control servo...

RE: Whiplash
 

Yes, I'm sorry - I read all of that but I have not exactly got all the interchangeablilities ([sm=spinnyeyes.gif] sorted out in my mind yet. Age.. damaged brain cells.. etc. Please don't think I'm not studying your very detailed and helpful posts!

I'm in the midst of a family emergency right now, but in 3-4 days I'll sketch up what I have in mind for streamlining, extra fuel capacity etc. and toss it to the wolves on here for dissection.

I think this project should be a riot. I don't care if deltas aren't the most efficient, I'm not trying to build a record breaker, but I am trying to build an honest 200 mph aircraft. Looks like the puzzle pieces are coming together. After this I'll get serious about a proper speed airframe. Or realize I should pursue something else..

MJD

RE: Whiplash
 

my mousse can beat the JETT pipe on the 25fx by at least 500 rpms. A couple of guys really pushed aggressivly JETT products (one of the distributors and a few guys here at RCUniverse), but I've never flown one, so I apolagize for any negative comments. Well, clearly I am a newbie incomparison to you guys. I almost purchased the JETT 60

I used a 12 oz Hayes tank from Tower hobbies and just had to mount servo for throttle in battery compartment area. The hayes tank matched width perfect but could be too tall for Rear Fire exhaust.

I wrapped the whole front area at engine mount with carbon fiber 5 oz cloth from Aerospace ABS AND c/f 1/8 rods down leading and side edge of wing and down middle bottom section of fuse, and cloth at rear tail of fuse. I think you might eventually break your engine mounts w/o reinforcement. My engine mount broke after a couple of tough landings.

Part of the problem is our field, it's paved and I don't have landing gear. During the summer it has no grass and patches of rock to the sides of the landing strip.

Good luck on your project, I would like to hear how it goes and see pics, thanks

RE: Whiplash
 

Mousse cans can kick-butt in some cases....

Jett rules, own one then comment.

RE: Whiplash
 

On the smaller 25 - 30 size engines you can sometimes find better performance with a mousse can setup. But, only because of the same reasons a full pipe might be better. You can build/tune the mousse can for the prop you want to use. Some folks have gotten great performance.

The jett muffler will out-perform stock - always. Most folks that do not see a significant performance gain (above the stock muffler) from the jett-stream muffler do not prop the engine for the rpm target range. On the smaller 25-35 size muffler, target peak ground rpm is 17,000 or better. Boost over stock muffler is 1200-1800 rpm on average.

Some mousse can guys flying the Outlaws and similar get similar or better performance.

This is a good reference thread on the performance - OS25.
http://www.rcuniverse.com/forum/fb.asp?m=3872394

RE: Whiplash
 

the ops is not designed for nitro and does it have any carb throttle function...

do you know the hp and weight

RE: Whiplash
 

You can run all the nitro you want (pretty much) if you reduce the compression ratio to suit - head shims. But yeah, as delivered the aero engines are set up for low to no nitro fuels. Since all they make now are marine engines, it is safe to say they are made to take nitro.

All of them have carb function, except the aero speed engines.

Everything you could possibly want to know about OPS at this point has been covered in awesome detail by I-Love-Jets on this forum, over the last 2-3 weeks. Just search OPS.

MJD

RE: Whiplash
 

I LOVE JETS:

Again I thank you for taking the time to respond. #3 seems the overall way to go for multiple type airframe use and is relatively simple to construct. I get a kick out of some of the youngsters thinking you can get good speed out of a OS sport engine that will run with a Jett or Nelson or Pico. The 90 VRDF is a different beed of cat as ar several other DF engines available. Have had a OS vrdf engine in the cabinet for a couple of years now waiting for a good overall airframe design of the wing thing type. Not looking for 200 mph, allready have several capable of low 200's, but fading eyesight and reactions make us something of a hazzard. The around 150's are still sound and safe, I think. Just want something stable, large enough to accommodate the 90 along with retract weight and decent fuel load. Of course it should be quick, otherwise a nap would be in order. Let me know if something comes to mind. Yea, still build from scratch. ENJOY