Excelsior's Cloud Hopper is a bunny themed kit bash of the Estes Baby Bertha to build an OOP Estes Cloud Hopper. My kids (5.5 and 7.5) chose this rocket for obvious reasons; some of their comments are included below. The Cloud Hopper debuted in the 1973 Estes Catalog. Mosquito Mike has a nice page with more history and examples of Estes Goonybirds. Excelsior gets into the fun by warning "Carrots not included!"
For $6 plus $4 shipping you get 2 pages of instructions including cardstock templates, 1 page of decal instructions, and 1/2 page of waterslide decals, including mouth and whisker lines in two color options. You must also buy a Baby Bertha kit ($4.69 + $5.95 shipping from Hobbylinc) and a small piece of 1/8" balsa (since the fins won't fit on the pre-cut 1/16" Baby Bertha sheet).
From the time I ordered, it was nearly three weeks until Excelsior's package arrived. I received an unsolicited email from Excelsior after about 10 days apologizing for the delay, which I greatly appreciated. The package arrived with ample cardboard protection to prevent bending of the decals.
Let me get my main gripe out of the way first, so I can focus on the positive aspects of the Cloud Hopper. I think $10 is pretty steep to pay for a set of decals and instructions considering it's only a couple sheets of paper being mailed and free Cloud Hopper instructions can be downloaded on JimZ's site.
Excelsior's build instructions constitute a list of exceptions to the Baby Bertha build, with no additional figures except an image of the finished model. The instructions could be improved by replacing their sequential numbering with a numbering system that referred directly to the Baby Bertha build steps so we know where each exception is supposed to occur in the build process ("Modify step 3 by..."). Also, there are various ambiguous references to gluing on "wings" where some people might be confused about which fins/wings are being referred to in various portions of the instructions. However, the assembly order doesn't matter much and most people will get everything in the right place.
The "leg" fins are not perfectly symmetric--there is a subtle sweep. It would be very easy to put these fins on backwards. My rudders were also not perfectly square, either by design or after the kids sanded them. Thus, attention was needed to choose the appropriate leading edge. The rudder templates include a slot for attachment to the horizontal stabilizer. I didn't notice this and had to cut the slots after sanding/sealing everything. This was my fault and the cardstock templates were excellent and indicated the grain and proper leading edge on each piece.
We deviated from the instructions in one important way. Excelsior's instructions place the rear centering ring back 1/2" from the lower edge of the motor mount tube, then ask that you glue the motor mount assembly so that the end of the motor hook is even with the bottom edge of the body tube, whereas the Baby Bertha instructions ask you to glue it so that the end of the motor mount tube is even with the bottom edge of the body tube. Excelsior explains that moving the motor forward like this improves stability. The engine hook in my Baby Bertha kit was one of the type with 3 bends in an S-shape at the bottom, not a simple 1-bend L-shape. Thus the difference in these two choices is about 3/4" (1/4" engine beyond MMT + 1/2" hook beyond engine). This left of cavity in the rear end of the rocket of up to 1.25" in depth to the aft CR. I was concerned about nestling the engine so deeply inside the body tube and getting heat damage to the body and/or a thrust-canceling Krushnik effect. So I compromised and I positioned things so the end of the motor itself would be even with the end of the body tube. My choice matches the original Cloud Hopper assembly from JimZ's site, except that there the lower CR is flush with the aft end of the MMT.
Excelsior asks you to add 3-4 grams of weight to the nose cone to ensure stability. I'm lucky enough to have a kitchen scale that measures in grams. Having deviated from the instructions in the placement of the motor, I used 8 grams in the nose cone to compensate.
We also used Kevlar® through the (paper) upper centering ring instead of an Estes 3-fold shock cord mount.
After lengthy and heated negotiations, the kids finally chose bright yellow Rustoleum gloss paint. Next came the decals--this is what you're really buying from Excelsior. There is a long, detailed page of instructions on the use and placement of the decals, along with a helpful figure. The decals went on great despite not using the specialty decal liquids mentioned in the instructions. Wrapping the decals around the tip of the nose cone was a bit tricky and left some wrinkled edges that cleaned up pretty well with eventual Future Floor Polish overcoat.
PROs: great "Goony" look, excellent decals and decal instructions
CONs: high cost, some ambiguities in the build instructions, questionable motor placement
Construction Rating: 4 out of 5
I emailed Excelsior the day before the launch asking for a motor recommendation, but understandably they weren't able to respond in time. So we chose an Estes B4-4 for the first flight.
Boost was low and fairly slow to a few hundred feet. Ejection was very late...that bunny was halfway back down to Earth before he shot his laundry. On landing, the rear portion of one of the rudders splintered. I tacked it back together with CA and fired him again. The second launch was nearly identical with slightly less suspense at ejection since we knew the delay was too long. The same rudder broke again and needs repairs.
Both flights were somewhat squirrelly. Spin a little here, wobble a little there, etc. Much like a bunny avoiding a hawk. This flight characteristic is probably caused by the large and complex fin area and by my kids' imprecision in assembly.
PROs: flies fine, ours will need a C to put it up high.
CONs: bottom-first landings have all those fins hitting first
Flight Rating: 3 out of 5
This rocket was a nice change of pace and an amusing diversion. We'll keep flying it until one day it goes to that great carrot patch in the sky.
Here are the kids' comments: "It was sort of hard building. It took a lot of work. The best part was putting on the decals. It was really exciting launching because you wouldn't really know when the parachute would come out. I would say 5 stars for flying."
Overall Rating: 4 out of 5