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RocHobby Critical Mass High Speed 1100mm (43") - PNP



RocHobby Critical Mass High Speed 1100mm (43") - PNP

24 reviews  | 

This product is discontinued

Spare parts available below

Regular price 199.99 $19999 Free Shipping*

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RocHobby Critical Mass High Speed 4S - Receiver Ready - ROC012-1

We felt the Critical Mass was deserving of a high speed power plant to give it the performance many are looking for. The Critical Mass was already one of the favorite planes around Motion RC but now it is even better. We added a larger 3648-770Kv motor, 70A ESC, and 9g metal gear servos. In addition the plane now runs on a 4 cell LiPo. The Critical Mass can now reach speeds of 90Mph and has unlimited vertical. The critical Mass still retains the amazing flight characteristics it has become known for. Landings are still slow and very predictable. It is a true joy to fly. Don't forget about the great features that made this plane popular in the first place. It still has split flaps, servoless electric retracts, and fantastic good looks.

Unlike many stock planes, this one is not underpowered at all. In fact, this plane may be too fast for some. We will retain the normal speed Critical Mass as a product since not everyone needs extreme speeds. The high speed Critical Mass will absolutely leave leave lesser planes in the dust. The high speed version has the same strong EPO foam construction and retains the nylon hinges for the split flaps. The retracts have proven very durable on the original Critical Mass so the same retracts with metal trunnions have been used again. The same upgraded problem free paint has been used to match the later versions of the regular speed Critical Mass. We at Motion RC think this is one of the most durable, most fun, best built planes on the market. Like all RocHobby planes, this one is made by FMS.


  • Able to achieve speeds of 90mph
  • 3648-770Kv motor and 70A ESC
  • Now uses a 4S 2200 LiPo
  • 9g metal gear servos for ailerons, rudder, elevator
  • Split flaps with nylon hinges
  • Servoless electric retracts with metal trunnions
  • EPO foam construction
  • Brushless motor, ESC and servos installed


  • Minimum 6 Channel Radio - Click Here for recommendations
  • 6 Channel Receiver - Click Here for recommendations
  • 4 Cell 14.8V 2500 mAh Lipo Battery - EPR25004PRO
  • Lipo Battery Charger - Click Here for recommendations

Product Specifications:

AGE LEVEL : 14 and up
SKILL LEVEL : Advanced
BUILD TIME : 1+ Hours


1100mm / 43.3in


918mm / 36.1in

Flying Weight


Power System

3648-770Kv brushless

Speed Control

70A, Integrated 5A SBEC, T Connector

Propeller / EDF

4 blade prop


9g×4 metal gear, 9gx2 standard (flap)

Landing Gear

Servoless electric retracts, metal trunnions

Required Battery

14.8V 2200mAh 30C 4 cell LiPo

Required Radio

6 Channel




Yes - split flaps





Hinge Type



EPO Foam

Product Questions & Answers

NOTE: Questions submitted on this page are answered by customers who have previously purchased this item. If you have a support related question that requires immediate assistance, please visit our Help Center.

Product Reviews

Customer Reviews
4.5 Based on 24 reviews
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Filter Reviews:
Larry L.
Very nice

Very nice

Bill i.
One solid airplane!

When I bought the first Critical Mass a year ago, my flights were accompanied by the "vibrating hands and knees" of a very nervous pilot. The more I flew her, it became clear the plane could fly beautifully at all speeds. The flaps work very well, and are designed to minimize pitch up when deployed. Landing gear is tough as nails and anchored well into the wing. Roc has always made a superior product, and this is no exception. Beautiful on the ground, beautiful in the air, and impressive low passes. This is a keeper. When I saw the price drop, I jumped on the chance to have a back up for One Solid Airplane!

Donald S.
Critical Mass

I received the Critical Mass foam plane from Motion RC and had it assembled in no time. I made a few adjustments to the control surfaces and it was out to the field for a test flight. I did have to put a touch of weight in the nose to balance it out but now it seems to be flying really great. This is mt second Critical Mass plane and I must say they both fly well. Thanks

Update: crash on maiden

My earlier review of 3 stars was based on some very minor flaws in the assembly, and an odd crash where I couldn't keep it from rolling and ended up crashing. It was not the aileron the control horn, as I previously suspected. The power wires from the ESC jammed between the rudder and elevator pushrod ends, seizing the servos in the left turn I was making to enter the pattern after take off. I didn't notice it that day, I was a little aggravated at the time. So, not the plane's fault - I routed the wires. Other than the minor issues mentioned in my previous review, I love the plane.

Some very good, some not so.

I received this yesterday for Christmas, and took it to the field to maiden today. On assembly, I noticed the control horns seemed thin and flimsy, the flaps "fit" a little too tightly into their recesses and hang up, and can't be trimmed without exposing white foam. The battery cover has a foam lip to hold the battery in place, but with an Admiral 4S 2200, I had to trim quite a bit of that lip for it to fit (yes, the battery was all the way forward). The rudder servo/pushrod/tail wheel set-up was all out of whack, but I got it worked out after dropping the servo arm screw into the belly of the beast a few times - and the set screw for the tail wheel adjustment needs to face downward for easier adjustment. The quality of materials, otherwise, was great. On the maiden take-off, it got up to speed smoothly, rotated and lifted as expected. In the turn to enter the pattern it suddenly rolled right (there were 15-20mph winds, to be fair), I tried to regain control but it was impossible - nothing I did translated to what should happen. I tried to get it flattened out before it hit the ground in the tall grass, but I couldn't keep it from trying to roll and it did a cartwheel, breaking the prop, spinner and both LG struts are badly bent (plastic portion of LG broke), and the cowl is a little compressed on the bottom. Upon inspection, I found the right (starboard) aileron control horn was broken off clean at its base. Was that the root cause? It makes sense, but who knows. Just in case, buy better quality horns for yours.

Very nice plane!

Completed the build on my Roc-Hobby Critical Mass which wasn't a build at all but just a quick attachment of the wing, tail, & a couple control horns install a receiver & battery & head to the field! The Roc-Hobby Critical Mass is a great flying, Fast & wonderful handling plane! Found no tendencies to Dutch Roll on final with a stiff cross-wind at all. It did take several go-arounds to get a slow enough approach so that it didn't balloon in ground effect just before touchdown, but this may also have been my unfamiliarity with the plane. One small problem & reason for the four stars is one of the retracts made a horrible screeching when activated it worked fine for about 3 batteries & has since failed! I will contact MRC cut. service for replacement! Other than that buy this plane Great Quality, Attracts a Crowd,& you will Love it!

goes together well

I have not flown the Critical mass yet, I hope to next week so my rating is only on the build. I give it 4 stars because I don't like the instruction manual. The photos are hard to see, and I don't follow the install time line. I found it's easier to go to each step as you feel is best for you. Following the book for me made no sense. It does go together well however and the parts are tight and fit well. I did have a problem with the spinner . I got the wrong one, goes to another plane. I'm still waiting for mine in the snail mail so I can fly the plane. I do trust Motion R/C and will shop there again.

Very nice but not as fast as advertised

I love this plane and the shipping was fast,but I ordered it because I wanted a fast racer. It flys great and is very nicely made but I can't see 90 mph. The split flaps are very nice and scale,the retracts are strong and smooth it slowed down to land like a trainer. Just disappointed with top speed I haven't radared it but it's only a little faster than my sukoui

James L.

Anyone hand launching this bird? I am about to scrap the retracts and flaps and put skid plates on it. No matter what I pay for retracts they are unreliable. That does not improve when you only pay 11.95 for them.